Updated on 2024/11/11

Information

 

写真a

 
TSUMURA KOJI
 
Organization
Faculty of Science Department of Physics Associate Professor
Research Center for Advanced Particle Physics (Concurrent)
School of Sciences Department of Physics(Concurrent)
Graduate School of Sciences Department of Physics(Concurrent)
Title
Associate Professor
Contact information
メールアドレス
Profile
素粒子についての現象論的研究を行っている。特に、ヒッグスボソンの物理、ニュートリノの物理、暗黒物質の物理を専門とし、それらの関係する新物理模型の構築および検証方法の提案を行っている。
External link

Degree

  • Ph. D.

Research History

  • 2013年12月 助教, 京都大学 2012年4月 特任助教, 名古屋大学 2010年10月 ポスドク研究員, 國立臺灣大學 (台湾, 台北市) 2007年10月 ポスドク研究員, 国際理論物理学センター (イタリア, トリエステ) 2007年4月 研究員(科学研究), 高エネルギー加速器研究機構   

Research Interests・Research Keywords

  • Research theme: New Physics Model

    Keyword: New Physics

    Research period: 2019.11 - 2020.3

  • Research theme: Higgs Physics

    Keyword: Higgs boson

    Research period: 2019.11 - 2020.3

  • Research theme: Neutrino Physics

    Keyword: Neutrino

    Research period: 2019.11 - 2020.3

  • Research theme: Dark Matter Physics

    Keyword: Dark Matter

    Research period: 2019.11 - 2020.3

Awards

  • 第11回(2016年度)素粒子メダル奨励賞

    2017.3   素粒子論グループ   濱田雄太(Yuta Hamada)、川名清晴(Kiyoharu Kawana)、津村浩二(Koji Tsumura) "Landau pole in the Standard Model with weakly interacting scalar fields", Physics Letter B747 (2015) 238

  • 第8回(2013年度)素粒子メダル奨励賞

    2014.3   素粒子論グループ   杉山弘晃(すぎやま ひろあき)、津村浩二(つむら こうじ)、横谷洋(よこや ひろし) "Discrimination of models including doubly charged scalar bosons by using tau lepton decay distributions" Hiroaki Sugiyama, Koji Tsumura, Hiroshi Yokoya, Physics Letters B717 (2012) 229.

Papers

  • Landau pole in the Standard Model with weakly interacting scalar fields Reviewed

    Yuta Hamada, Kiyoharu Kawana, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   747   238 - 244   2015.7

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    We consider the Standard Model with a new scalar field X which is an nX representation of the SU(2)L with a hypercharge YX. The renormalization group running effects on the new scalar quartic coupling constants are evaluated. Even if we set the scalar quartic coupling constants to be zero at the scale of the new scalar field, the coupling constants are induced by the one-loop effect of the weak gauge bosons. Once non-vanishing couplings are generated, the couplings rapidly increase by renormalization group effect of the quartic coupling constant itself. As a result, the Landau pole appears below Planck scale if nX≥4. We find that the scale of the obtained Landau pole is much lower than that evaluated by solving the one-loop beta function of the gauge coupling constants.

    DOI: 10.1016/j.physletb.2015.05.072

    Repository Public URL: http://hdl.handle.net/2324/4796003

  • Fingerprinting nonminimal Higgs sectors Reviewed

    Shinya Kanemura, Koji Tsumura, Kei Yagyu, Hiroshi Yokoya

    Physical Review D - Particles, Fields, Gravitation and Cosmology   90 ( 7 )   2014.10

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    After the discovery of the standard model-like Higgs boson at the LHC, the structure of the Higgs sector remains unknown. We discuss how it can be determined by the combination of direct and indirect searches for additional Higgs bosons at future collider experiments. First of all, we evaluate expected excluded regions for the mass of additional neutral Higgs bosons from direct searches at the LHC with the 14 TeV collision energy in the two Higgs doublet models with a softly broken Z2 symmetry. Second, precision measurements of the Higgs boson couplings at future experiments can be used for the indirect search of extended Higgs sectors if the measured coupling constant with the gauge boson slightly deviates from the standard model value. In particular, in the two Higgs doublet model with the softly broken discrete symmetry, there are four types of Yukawa interactions, so that they can be discriminated by measuring the pattern of deviations in Yukawa coupling constants. Furthermore, we can fingerprint various extended Higgs sectors with future precision data by detecting the pattern of deviations in the coupling constants of the standard model-like Higgs boson. We demonstrate how the pattern of deviations can be different among various Higgs sectors that predict the electroweak rho parameter to be unity, such as models with additional an isospin singlet, a doublet, triplets, or a septet. We conclude that, as long as the gauge coupling constant of the Higgs boson slightly differs from the standard model prediction but is enough to be detected at the LHC and its high-luminosity run or at the International Linear Collider, we can identify the nonminimal Higgs sector even without direct discovery of additional Higgs bosons at the LHC.

    DOI: 10.1103/PhysRevD.90.075001

    Repository Public URL: http://hdl.handle.net/2324/4795991

  • Weakly interacting massive particle dark matter and radiative neutrino mass from Peccei-Quinn symmetry Reviewed

    Basudeb Dasgupta, Ernest Ma, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   89 ( 4 )   2014.2

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    The Peccei-Quinn anomalous global U(1)PQ symmetry is important for solving the strong CP problem with a cosmologically relevant axion. We add to this the simple (but hitherto unexplored) observation that it also has a residual Z2 symmetry which may be responsible for a second component of dark matter, i.e., an absolutely stable weakly interacting singlet scalar. This new insight provides a theoretical justification for this simplest of all possible dark-matter models. It also connects with the notion of generating radiative neutrino mass through dark matter. Two such specific realizations are proposed. In our general scenario, dark-matter detection is guaranteed at existing direct-detection experiments and/or axion searches. Observable signals at the Large Hadron Collider are discussed.

    DOI: 10.1103/PhysRevD.89.041702

    Repository Public URL: http://hdl.handle.net/2324/4795989

  • Higgs boson mixes with an SU(2) septet representation Reviewed

    Junji Hisano, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   87 ( 5 )   2013.3

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    We study the possibility of the Higgs boson, which consists of an SU(2) doublet and a septet. The vacuum expectation value of a septet with hypercharge Y=2 is known to preserve the electroweak rho parameter unity at the tree level. Therefore, the septet can give a significant contribution to the electroweak symmetry breaking. Because of the mixing with the septet, the gauge coupling of the standard-model-like Higgs boson is larger than that in the standard model. We show the sizable vacuum expectation value of the Higgs septet can be allowed under the constraint from the electroweak precision data. The signal strengths of the Higgs boson for the diphoton and a pair of weak gauge boson decay channels at the LHC are enhanced, while those for the fermionic decay modes are suppressed. The mass of additional neutral Higgs boson is also bounded by the current LHC data for the standard model Higgs boson. We discuss the phenomenology of the multiply charged Higgs bosons, which come from the septet.

    DOI: 10.1103/PhysRevD.87.053004

    Repository Public URL: http://hdl.handle.net/2324/4795981

  • Lepton number violation at the LHC with leptoquark and diquark Reviewed

    Masaya Kohda, Hiroaki Sugiyama, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   718 ( 4-5 )   1436 - 1440   2013.1

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    We investigate a model in which tiny neutrino masses are generated at the two-loop level by using scalar leptoquark and diquark multiplets. The diquark can be singly produced at the LHC, and it can decay into a pair of leptoquarks through the lepton number violating interaction. Subsequent decays of the two leptoquarks can provide a clear signature of the lepton number violation, namely two QCD jets and a pair of same-signed charged leptons without missing energy. We show that the signal process is not suppressed while neutrino masses are appropriately suppressed.

    DOI: 10.1016/j.physletb.2012.12.048

    Repository Public URL: http://hdl.handle.net/2324/4795980

  • Discrimination of models including doubly charged scalar bosons by using tau lepton decay distributions Reviewed

    Hiroaki Sugiyama, Koji Tsumura, Hiroshi Yokoya

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   717 ( 1-3 )   229 - 234   2012.10

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    The doubly charged scalar boson (H ±±) is introduced in several models of the new physics beyond the standard model. The H ±± has Yukawa interactions with two left-handed charged leptons or two right-handed charged leptons depending on the models. We study kinematical properties of H ±± decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of the tau decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the H ±± decay products. We perform simulation studies for the typical decay patterns of the H ±± with simple event selections and tau-tagging procedures, and show that the chiral structure of the Yukawa interactions of H ±± can be distinguished by measuring the invariant-mass distributions.

    DOI: 10.1016/j.physletb.2012.09.044

    Repository Public URL: http://hdl.handle.net/2324/4795979

  • QCD corrections to neutron electric dipole moment from dimension-six four-quark operators Reviewed

    Junji Hisano, Koji Tsumura, Masaki J.S. Yang

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   713 ( 4-5 )   473 - 480   2012.7

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    In this Letter, the renormalization-group equations for the (flavor-conserving) CP-violating interaction are derived up to the dimension six, including all the four-quark operators, at one-loop level. We apply them to the models with the neutral scalar boson or the color-octet scalar boson which have CP-violating Yukawa interactions with quarks, and discuss the neutron electric dipole moment in these models.

    DOI: 10.1016/j.physletb.2012.06.038

    Repository Public URL: http://hdl.handle.net/2324/4795786

  • Search for doubly charged Higgs bosons using the same-sign diboson mode at the LHC Reviewed

    Cheng Wei Chiang, Takaaki Nomura, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   85 ( 9 )   2012.5

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    Doubly charged Higgs bosons are predicted in many new physics models with an extended Higgs sector that contains a Higgs triplet field. Current experimental searches have been focusing mainly on the scenario in which the same-sign dilepton decay modes are the dominant ones. We study the scenario where the vacuum expectation value of the triplet field is sufficiently large so that the associated charged Higgs bosons decay dominantly to a pair of weak gauge bosons instead. A detailed simulation of the signal and the backgrounds is performed for the CERN Large Hadron Collider (LHC) at the collision energy of 8 TeV and 14 TeV. We find that different cuts should be imposed for the events, depending on whether the doubly charged Higgs boson mass is greater than about 200 GeV. In the higher mass region, the forward jet tagging proves to be useful in enhancing the signal significance. We show the discovery reach of the LHC running at 8 and 14 TeV, with two benchmark triplet vacuum expectation values. With an integrated luminosity of 10fb -1 at 8 TeV, the doubly charged Higgs boson with a mass of ∼180GeV can be tested at 5σ level in such a scenario.

    DOI: 10.1103/PhysRevD.85.095023

    Repository Public URL: http://hdl.handle.net/2324/4795783

  • Indirect bounds on heavy scalar masses of the two-Higgs-doublet model in light of recent Higgs boson searches Reviewed

    Shinya Kanemura, Yasuhiro Okada, Hiroyuki Taniguchi, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   704 ( 4 )   303 - 307   2011.10

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    We study an upper bound on masses of additional scalar bosons from the electroweak precision data and theoretical constraints such as perturbative unitarity and vacuum stability in the two-Higgs-doublet model taking account of recent Higgs boson search results. If the mass of the Standard-Model-like Higgs boson is rather heavy and is outside the allowed region by the electroweak precision data, such a discrepancy should be compensated by contributions from the additional scalar bosons. We show the upper bound on masses of the additional scalar bosons to be about 2 (1) TeV for the mass of the Standard-Model-like Higgs boson to be 240 (500) GeV.

    DOI: 10.1016/j.physletb.2011.09.035

    Repository Public URL: http://hdl.handle.net/2324/4795559

  • Higgs boson pair production in new physics models at hadron, lepton, and photon colliders Reviewed

    Eri Asakawa, Daisuke Harada, Shinya Kanemura, Yasuhiro Okada, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   82 ( 11 )   2010.12

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    We study Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models; i.e., the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth generation fermion model and the vectorlike quark model. Cross sections for these processes can deviate significantly from the standard model predictions due to the one-loop correction to the triple Higgs boson coupling constant. For the one-loop induced processes such as gg→hh and γγ→hh, where h is the (lightest) Higgs boson and g and γ respectively represent a gluon and a photon, the cross sections can also be affected by new physics particles via additional one-loop diagrams. In the two-Higgs-doublet model and scalar leptoquark models, cross sections of e +e-→hhZ and γγ→hh can be enhanced due to the nondecoupling effect in the one-loop corrections to the triple Higgs boson coupling constant. In the sequential fourth generation fermion model, the cross section for gg→hh becomes very large because of the loop effect of the fermions. In the vectorlike quark model, effects are small because the theory has decoupling property. Measurements of the Higgs boson pair production processes can be useful to explore new physics through the determination of the Higgs potential.

    DOI: 10.1103/PhysRevD.82.115002

    Repository Public URL: http://hdl.handle.net/2324/4795558

  • Models of Yukawa interaction in the two Higgs doublet model, and their collider phenomenology Reviewed

    Mayumi Aoki, Shinya Kanemura, Koji Tsumura, Kei Yagyu

    Physical Review D - Particles, Fields, Gravitation and Cosmology   80 ( 1 )   2009.8

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    Possible models of Yukawa interaction are discussed in the two Higgs doublet model (THDM) under the discrete symmetry imposed to avoid the flavor changing neutral current at the leading order. It is known that there are four types of such models corresponding to the possible different assignment of charges for the discrete symmetry on quarks and leptons. We first examine the decay properties of Higgs bosons in each type model, and summarize constraints on the models from current experimental data. We then shed light on the differences among these models in collider phenomenology. In particular, we mainly discuss the so-called type-II THDM and type-X THDM. The type-II THDM corresponds to the model with the same Yukawa interaction as the minimal supersymmetric standard model. On the other hand, in the type-X THDM, additional Higgs bosons can predominantly decay into leptons. This scenario may be interesting because of the motivation for a light charged Higgs boson scenario such as in the TeV-scale model of neutrinos, dark matter, and baryogenesis. We study how we can distinguish the type-X THDM from the minimal supersymmetric standard model at the Large Hadron Collider and the International Linear Collider.

    DOI: 10.1103/PhysRevD.80.015017

    Repository Public URL: http://hdl.handle.net/2324/4795523

  • Lepton flavor violation in Higgs boson decays under the rare tau decay results Reviewed

    Shinya Kanemura, Toshihiko Ota, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   73 ( 1 )   2006.1

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    We study lepton flavor violation (LFV) associated with tau leptons in the framework of the two Higgs doublet model, in which LFV couplings are introduced as a deviation from Model II Yukawa interaction. Parameters of the model are constrained from experimental results and also from requirements of theoretical consistencies such as vacuum stability and perturbative unitarity. Current data for rare tau decays provide substantial upper limits on the LFV Yukawa couplings in the large tanβ region (tanβ30), which are comparable with predictions in fundamental theories. Here tanβ is the ratio of vacuum expectation values of the two Higgs doublets. We show that a search for the LFV decays 0→τ±μ (τ±e) of neutral Higgs bosons (0=h,H and A) at future collider experiments can be useful to further constrain the LFV couplings especially in the relatively small tanβ region (tanβ30), where rare tau decay data cannot give any strong limit.

    DOI: 10.1103/PhysRevD.73.016006

    Repository Public URL: http://hdl.handle.net/2324/4795149

  • Search for lepton flavor violation in the Higgs boson decay at a linear collider Reviewed

    Shinya Kanemura, Koichi Matsuda, Toshihiko Ota, Tetsuo Shindou, Eiichi Takasugi, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   599 ( 1-2 )   83 - 91   2004.10

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    We discuss possibility of direct search for lepton flavor violation (LFV) in Yukawa interaction by measuring the branching ratio for the decay of the lightest Higgs boson (h 0) into a τ-μ pair at a linear collider (LC). We study the significance of the signal process, e +e -→Z*→Zh 0→Zτ ±μ , against the backgrounds such as e +e -→Zτ +τ -→Zτ ±μ + missings. After taking appropriate kinematic cuts, the number of the background event is considerably reduced, so that the signal can be visible when the branching ratio of h 0→τ ±μ is larger than about 10 -4. In a minimal supersymmetric Standard Model scenario, the effective coupling of h 0τ ±μ can be generated at the loop level due to the slepton mixing. When supersymmetric mass parameters are larger than TeV scales, the branching ratio can be as large as several times 10 -4. Therefore, the signal can be marginally visible at a LC. In the general two-Higgs-doublet model, the possible maximal value for the branching ratio of h 0→τ ±μ can reach to a few times 10 -3 within the available experimental bound, so that we can obtain larger significance.

    DOI: 10.1016/j.physletb.2004.08.024

    Repository Public URL: http://hdl.handle.net/2324/4795517

  • Nambu-Goldstone modes in magnetized T2n extra dimensions

    Hirose T., Otsuka H., Tsumura K., Uchida Y.

    Physical Review D   110 ( 3 )   2024.8   ISSN:24700010

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    We consider a U(1) gauge theory on M4×T4 with background magnetic fluxes. We show that a theory including arbitrary fluxes can always be studied in a theory involving only diagonal fluxes by appropriate coordinate transformations. It is found that the number of independent magnetic fluxes is equal to the rank of the classical value of the field strength matrix, rank F. The number of massless zero modes induced from extra components of higher-dimensional gauge field (Wilson-line scalar field) is also determined by rank F. We explicitly confirm that the quantum corrections due to the matter fermion to the squared mass of the Wilson-line scalar field cancel out at the one-loop level. For this purpose, we derive the fermion mass spectrum on M4×T4 with arbitrary fluxes. By taking the flux diagonal basis, creation and annihilation operators for Kaluza-Klein quantum numbers are defined appropriately. Our results are easily generalized to the case of M4×T2n(n≥3).

    DOI: 10.1103/PhysRevD.110.035032

    Scopus

  • A model of pseudo-Nambu-Goldstone dark matter with two complex scalars

    Abe, T; Hamada, Y; Tsumura, K

    JOURNAL OF HIGH ENERGY PHYSICS   2024 ( 5 )   2024.5   ISSN:1029-8479

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    Publisher:Journal of High Energy Physics  

    Pseudo-Nambu-Goldstone (pNG) dark matter (DM) is a promising DM candidate and able to explain the measured DM abundance by the thermal freeze-out mechanism evading the stringent bound from DM direct detection experiments. We propose a new model providing a pNG DM by introducing two Standard-Model-singlet complex scalars with the same charges of a dark U(1) gauge symmetry. They are also charged under a U(1) global symmetry corresponding to their relative phase rotations, which is explicitly broken by a soft-breaking term in the scalar potential. The both U(1) symmetries are spontaneously broken by their vacuum expectation values, giving rise to one real pNG boson. We also introduce a discrete ℤ2 symmetry exchanging the two scalars to stabilize the pNG boson as DM. It is shown that this model reproduces the DM abundance consistently with the current bound from the direct detection experiments. The model has a gauge kinetic mixing between the dark and U(1)Y gauge fields, which allows the dark gauge boson to decay even with a relatively light mass and prevents it from being an additional DM component. The Landau pole is avoided thanks to the small gauge coupling constant. In addition, a DM pair dominantly annihilates into a pair of the dark gauge bosons if the gauge boson mass is lighter than the DM mass, and thus its cross section has significantly different parameter dependence from other pNG DM models. We also calculate the DM-nucleon scattering cross section at the loop level. It turns out that it is necessary to probe region covered by the neutrino fog in order to test this model.

    DOI: 10.1007/JHEP05(2024)076

    Web of Science

    Scopus

  • Pseudo-Nambu-Goldstone Dark Matter in SU(7) Grand Unification Reviewed International journal

    Cheng-Wei Chiang, Koji Tsumura, Yoshiki Uchida, Naoki Yamatsu

    Physical Review D   2024.3

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    DOI: https://doi.org/10.1103/PhysRevD.109.055040

  • Pseudo-Nambu-Goldstone Dark Matter from Non-Abelian Gauge Symmetry Reviewed International journal

    Hajime Otsuka, Takashi Shimomura, Koji Tsumura, Yoshiki Uchida, Naoki Yamatsu

    Physical Review D   2022.12

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    DOI: https://doi.org/10.1103/PhysRevD.106.115033

  • Scalar Dark Matter with a μ-τ Flavored Mediator Reviewed International journal

    Kento Asai, Coh Miyao, Shohei Okawa, Koji Tsumura

    Physical Review D   2022.8

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    DOI: https://doi.org/10.1103/PhysRevD.106.035017

  • Baryon number non-conservation as Peccei-Quinn mechanism Reviewed International journal

    Takahiro Ohata, Kengo Takeuchi, Koji Tsumura

    Physical Review D   2021.8

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    Baryon number is an accidental symmetry in the standard model, while Peccei-Quinn symmetry is hypothetical symmetry which is introduced to solve the strong CP problem. We study the possible connections between Peccei-Quinn symmetry and baryon number symmetry. In this framework, an axion is identified as the Nambu-Goldstone boson of baryon number violation. As a result, characteristic baryon number violating processes are predicted. We developed the general method to determine the baryon number and lepton number of new scalar in the axion model.

    DOI: https://doi.org/10.1103/PhysRevD.104.035026

    Other Link: https://doi.org/10.1103/PhysRevD.104.035026

    Repository Public URL: http://hdl.handle.net/2324/4795130

  • Pseudo-Nambu-Goldstone Dark Matter Model Inspired by Grand Unification Reviewed International journal

    Yoshihiko Abe, Takashi Toma, Koji Tsumura, Naoki Yamatsu

    Physical Review D   2021.8

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    A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark matter (DM) due to the simple evasion of the current severe limits of DM direct detection experiments. One of the pNGB DM models has been proposed based on a {\it gauged} U(1)B−L symmetry. The pNGB has long enough lifetime to be a DM and thermal relic abundance of pNGB DM can be fit with the observed value against the constraints on the DM decays from the cosmic-ray observations. The pNGB DM model can be embedded into an SO(10) pNGB DM model in the framework of an SO(10) grand unified theory, whose SO(10) is broken to the Pati-Salam gauge group at the unified scale, and further to the Standard Model gauge group at the intermediate scale. Unlike the previous pNGB DM model, the parameters such as the gauge coupling constants of U(1)B−L, the kinetic mixing parameter of between U(1)Y and U(1)B−L are determined by solving the renormalization group equations for gauge coupling constants with appropriate matching conditions. From the constraints of the DM lifetime and gamma-ray observations, the pNGB DM mass must be less than (100)GeV. We find that the thermal relic abundance can be consistent with all the constraints when the DM mass is close to half of the CP even Higg masses.

    DOI: https://doi.org/10.1103/PhysRevD.104.035011

    Other Link: https://doi.org/10.1103/PhysRevD.104.035011

    Repository Public URL: http://hdl.handle.net/2324/4795131

  • Scalar and fermion on-shell amplitudes in generalized Higgs effective field theory Reviewed International journal

    Ryo Nagai, Masaharu Tanabashi, Koji Tsumura, Yoshiki Uchida

    Physical Review D   2021.7

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    Beyond-the-standard-model (BSM) particles should be included in effective field theory in order to compute the scattering amplitudes involving these extra particles. We formulate an extension of Higgs effective field theory which contains an arbitrary number of scalar and fermion fields with arbitrary electric and chromoelectric charges. The BSM Higgs sector is described by using the nonlinear sigma model in a manner consistent with the spontaneous electroweak symmetry breaking. The chiral-order counting rule is arranged consistently with the loop expansion. The leading-order Lagrangian is organized in accord with the chiral-order counting rule. We use a geometrical language to describe the particle interactions. The parametrization redundancy in the effective Lagrangian is resolved by describing the on-shell scattering amplitudes only with the covariant quantities in the scalar/fermion field space. We introduce a useful coordinate (normal coordinate), which simplifies the computations of the on-shell amplitudes significantly. We show that the high-energy behaviors of the scattering amplitudes determine the “curvature tensors” in the scalar/fermion field space. The massive spinor–wave function formalism is shown to be useful in the computations of on-shell helicity amplitudes.

    DOI: https://doi.org/10.1103/PhysRevD.104.015001

    Other Link: https://doi.org/10.1103/PhysRevD.104.015001

    Repository Public URL: http://hdl.handle.net/2324/4795132

  • Search for U(1)Lμ - Lτ charged Dark Matter with neutrino telescope Reviewed International journal

    Kento Asai, Shohei Okawa, Koji Tsumura

    Journal of High Energy Physics   2021.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

    We study a simple Dirac fermion dark matter model in U(1)Lμ−Lτ theory. The new light gauge boson X plays important roles in both dark matter physics and the explanation for the muon g−2 anomaly. The observed dark matter relic density is realized by a large U(1)Lμ−Lτ charge without introducing a resonance effect of the X boson. As a by-product of the model, characteristic neutrino signatures from sub-GeV dark matter ψ are predicted depending on the mass spectrum. We formulate the analysis of ψψ¯→νν¯, and of ψψ¯→XX followed by X→νν¯, in a model independent way. The energy spectrum of neutrinos in the former process is monochromatic while in the latter process is bowl-shape. We also evaluate sensitivity at Super-Kamiokande and future Hyper-Kamiokande detectors. The analysis is finally applied to the U(1)Lμ−Lτ dark matter model.

    DOI: https://doi.org/10.1007/JHEP03(2021)047

    Other Link: https://doi.org/10.1007/JHEP03(2021)047

    Repository Public URL: http://hdl.handle.net/2324/4797836

  • Scalegenesis and fermionic dark matters in the flatland scenario Reviewed

    Yu Hamada, Koji Tsumura, Masatoshi Yamada

    European Physical Journal C   80 ( 5 )   2020.5

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    We propose an extension of the standard model with Majorana-type fermionic dark matters based on the flatland scenario where all scalar coupling constants, including scalar mass terms, vanish at the Planck scale, i.e. the scalar potential is flat above the Planck scale. This scenario could be compatible with the asymptotic safety paradigm for quantum gravity. We search the parameter space so that the model reproduces the observed values such as the Higgs mass, the electroweak vacuum and the relic abundance of dark matter. We also investigate the spin-independent elastic cross section for the Majorana fermions and a nucleon. It is shown that the Majorana fermions as dark matter candidates could be tested by dark matter direct detection experiments such as XENON, LUX and PandaX-II. We demonstrate that within the minimal setup compatible with the flatland scenario at the Planck scale or asymptotically safe quantum gravity, the extended model could have a strong predictability.

    DOI: 10.1140/epjc/s10052-020-7929-3

    Repository Public URL: http://hdl.handle.net/2324/4822546

  • Pseudo-Nambu-Goldstone dark matter from gauged U(1)B-L symmetry Reviewed

    Yoshihiko Abe, Takashi Toma, Koji Tsumura

    Journal of High Energy Physics   2020 ( 5 )   2020.5

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    A pseudo-Nambu-Goldstone boson (pNGB) is an attractive candidate for dark matter since the current severe limits of dark matter direct detection experiments are naturally evaded by its nature. We construct a model with pNGB dark matter based on a gauged U (1)B−L symmetry, where no adhoc global symmetry is assumed. The model keeps natural suppression mechanism for the dark matter direct detection cross section. On the other hand, the pNGB can decay through the new high scale suppressed operators. We show that the pNGB has long enough lifetime to be a dark matter in the wide range of the parameter space of the model. The thermal relic abundance of pNGB dark matter can be fit with the observed value against the constraints on the dark matter decays from the cosmic-ray observations.

    DOI: 10.1007/JHEP05(2020)057

    Repository Public URL: http://hdl.handle.net/2324/4797834

  • QED background against atomic neutrino process with initial spatial phase Reviewed

    Minoru Tanaka, Koji Tsumura, Noboru Sasao, Satoshi Uetake, Motohiko Yoshimura

    European Physical Journal Plus   135 ( 3 )   2020.3

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    Atomic deexcitation emitting a neutrino pair and a photon is expected to provide a novel method of neutrino physics if it is enhanced by quantum coherence in a macroscopic target. However, the same enhancement mechanism may also lead to a serious problem of enhanced QED background process. We show that the QED background can be suppressed enough in the photonic crystal waveguide by using the spatial phase that is imprinted in the process of initial coherence generation in the target at excitation.

    DOI: 10.1140/epjp/s13360-020-00290-2

    Repository Public URL: http://hdl.handle.net/2324/4822544

  • Symmetry and geometry in a generalized Higgs effective field theory Finiteness of oblique corrections versus perturbative unitarity Reviewed

    Ryo Nagai, Masaharu Tanabashi, Koji Tsumura, Yoshiki Uchida

    Physical Review D   100 ( 7 )   2019.10

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    We formulate a generalization of Higgs effective field theory (HEFT) including an arbitrary number of extra neutral and charged Higgs bosons - a generalized HEFT (GHEFT) - to describe nonminimal electroweak symmetry breaking models. Using the geometrical form of the GHEFT Lagrangian, which can be regarded as a nonlinear sigma model on a scalar manifold, it is shown that the scalar boson scattering amplitudes are described in terms of the Riemann curvature tensor (geometry) of the scalar manifold and the covariant derivatives of the potential. The coefficients of the one-loop divergent terms in the oblique correction parameters S and U can also be written in terms of the Killing vectors (symmetry) and the Riemann curvature tensor (geometry). It is found that the perturbative unitarity of the scattering amplitudes involving the Higgs bosons and the longitudinal gauge bosons demands that the scalar manifold be flat. The relationship between the finiteness of the electroweak oblique corrections and the perturbative unitarity of the scattering amplitudes is also clarified in this language: we verify that once the tree-level unitarity is ensured, the one-loop finiteness of the oblique correction parameters S and U is automatically guaranteed.

    DOI: 10.1103/PhysRevD.100.075020

    Repository Public URL: http://hdl.handle.net/2324/4822543

  • A μ-τ-philic scalar doublet under Zn flavor symmetry Reviewed

    Yoshihiko Abe, Takashi Toma, Koji Tsumura

    Journal of High Energy Physics   2019 ( 6 )   2019.6

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    We propose a minimal model which accommodates the long-standing anomaly of muon magnetic moment based on abelian discrete flavor symmetries. The standard model is extended by scalar doublets charged under a Zn lepton flavor symmetry. In these models, a large contribution to the muon magnetic moment can be obtained by the chirality enhancement from new scalar mediated diagrams without conflicting with the flavor symmetry. Thanks to the lepton flavor symmetry, these models automatically forbid lepton flavor violation. The minimal model is based on Z4 symmetry with only one extra scalar doublet. In this model, we show that the parameter space favored by the muon g − 2 can easily be consistent with experimental constraints and theoretical bounds such as the electroweak precision tests, lepton universality, potential stability condition and triviality bound as well as the LHC direct search mass bound. The new contributions to the muon electric dipole moment and the Higgs decay into γγ can be indirect signals of the model.

    DOI: 10.1007/JHEP06(2019)142

    Repository Public URL: http://hdl.handle.net/2324/4822539

  • Minimal Gauged U(1)Lα - Lβ Models Driven into a Corner Reviewed

    Kento Asai, Koichi Hamaguchi, Natsumi Nagata, Shih Yen Tseng, Koji Tsumura

    Physical Review D   99 ( 5 )   2019.3

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    It is well known that the differences between the lepton numbers can be gauged with the standard model matter content. Such extended gauge theories, dubbed as the gauged U(1)Lα-Lβ models, have been widely discussed so far as potential candidates for physics beyond the Standard Model. In this work, we study the minimal versions of these gauge theories, where three right-handed neutrinos as well as a single U(1)Lα-Lβ symmetry breaking Higgs field - an SU(2)L singlet or doublet - are introduced. In these minimal models, the neutrino mass terms are constrained by the gauge symmetry, which result in the two-zero texture or two-zero minor structure of neutrino mass matrices. Such restrictive forms of neutrino mass matrices lead to nontrivial predictions for the neutrino oscillation parameters as well as the size of the mass eigenvalues. We find that due to this restriction the minimal gauged U(1)Lα-Lβ models are either incompatible with the observed values of the neutrino parameters or in strong tension with the Planck 2018 limit on the sum of the neutrino masses. Only the U(1)Lμ-Lτ model with an SU(2)L singlet U(1)Lμ-Lτ-breaking field barely evades the limit, which can be tested in the future neutrino experiments.

    DOI: 10.1103/PhysRevD.99.055029

    Repository Public URL: http://hdl.handle.net/2324/4797820

  • Charged scalars confronting neutrino mass and muon g − 2 anomaly Reviewed

    Nabarun Chakrabarty, Cheng Wei Chiang, Takahiro Ohata, Koji Tsumura

    Journal of High Energy Physics   2018 ( 12 )   2018.12

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    The present work introduces two possible extensions of the Standard Model Higgs sector. In the first case, the Zee-Babu type model for the generation of neutrino mass is augmented with a scalar triplet and additional singly charged scalar singlets. The second scenario, on the other hand, generalizes the Type-II seesaw model by replicating the number of the scalar triplets. A ℤ3 symmetry is imposed in case of both the scenarios, but, allowed to be violated by terms of mass dimension two and three for generating neutrino masses and mixings. We examine how the models so introduced can explain the experimental observation on the muon anomalous magnetic moment. We estimate the two-loop contribution to neutrino mass induced by the scalar triplet, in addition to what comes from the doubly charged singlet in the usual Zee-Babu framework, in the first model. On the other hand, the neutrino mass arises in the usual Type-II fashion in the second model. In addition, the role of the ℤ3 symmetry in suppressing lepton flavor violation is also elucidated.

    DOI: 10.1007/JHEP12(2018)104

    Repository Public URL: http://hdl.handle.net/2324/4798524

  • Syndetic extension of baryon and lepton numbers Proton decay and long-lived dark matter Reviewed

    Ernest Ma, Koji Tsumura

    Physical Review D   98 ( 3 )   2018.8

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    The well-known baryon and lepton numbers of the standard model of quarks and leptons are extended to include new fermions and bosons in a simple structure with several essential features. The usual heavy right-handed neutrino singlets (for neutrino mass and leptogenesis) are related to the axion which solves the strong CP problem. At the same time, baryon number is broken softly, allowing the proton to decay. Associated with this breaking, a long-lived dark-matter candidate (called the pseudosakharon) emerges. This new insight connects proton decay to a new component of dark matter.

    DOI: 10.1103/PhysRevD.98.035037

    Repository Public URL: http://hdl.handle.net/2324/4798522

  • Model with a gauged lepton flavor SU(2) symmetry Reviewed

    Cheng Wei Chiang, Koji Tsumura

    Journal of High Energy Physics   2018 ( 5 )   2018.5

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    We propose a model having a gauged SU(2) symmetry associated with the second and third generations of leptons, dubbed SU(2)μτ, of which U(1)Lμ−Lτ is an Abelian subgroup. In addition to the Standard Model fields, we introduce two types of scalar fields. One exotic scalar field is an SU(2)μτdoublet and SM singlet that develops a nonzero vacuum expectation value at presumably multi-TeV scale to completely break the SU(2)μτsymmetry, rendering three massive gauge bosons. At the same time, the other exotic scalar field, carrying electroweak as well as SU(2)μτcharges, is induced to have a nonzero vacuum expectation value as well and breaks mass degeneracy between the muon and tau. We examine how the new particles in the model contribute to the muon anomalous magnetic moment in the parameter space compliant with the Michel decays of tau.

    DOI: 10.1007/JHEP05(2018)069

    Repository Public URL: http://hdl.handle.net/2324/4798378

  • Effects of initial spatial phase in radiative neutrino pair emission Reviewed

    Minoru Tanaka, Koji Tsumura, Noboru Sasao, Satoshi Uetake, Motohiko Yoshimura

    Physical Review D   96 ( 11 )   2017.12

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    We study radiative neutrino pair emission in a deexcitation process of atoms taking into account the coherence effect in a macroscopic target system. In the course of preparing the coherent initial state to enhance the rate, a spatial phase factor is imprinted on the macroscopic target. It is shown that this initial spatial phase changes the kinematics of the radiative neutrino pair emission. We investigate effects of the initial spatial phase in the photon spectrum of the process. It turns out that the initial spatial phase provides us with significant improvements in exploring neutrino physics, such as the Dirac-Majorana distinction and the cosmic neutrino background.

    DOI: 10.1103/PhysRevD.96.113005

    Repository Public URL: http://hdl.handle.net/2324/4798376

  • Majoron as the QCD axion in a radiative seesaw model Reviewed

    Ernest Ma, Takahiro Ohata, Koji Tsumura

    Physical Review D   96 ( 7 )   2017.10

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    The smallness of neutrino mass, the strong CP problem, and the existence of dark matter are explained in an economical way. The neutrino mass is generated by the colored version of a radiative seesaw mechanism by using color adjoint mediators. The Majorana mass term of the adjoint fermion, which carries lepton number U(1)L, is induced by its spontaneous breaking, resulting in a Majoron which doubles as the quantum chromodynamics axion, thereby solving the strong CP problem. The breaking of U(1)L sets simultaneously the seesaw scale for neutrino mass and the Peccei-Quinn breaking scale. This axion is a good candidate for dark matter as usually assumed.

    DOI: 10.1103/PhysRevD.96.075039

    Repository Public URL: http://hdl.handle.net/2324/4797989

  • A radiative neutrino mass model with SIMP dark matter Reviewed

    Shu Yu Ho, Takashi Toma, Koji Tsumura

    Journal of High Energy Physics   2017 ( 7 )   2017.7

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    We propose the first viable radiative seesaw model, in which the neutrino masses are induced radiatively via the two-loop Feynman diagram involving Strongly Interacting Massive Particles (SIMP). The stability of SIMP dark matter (DM) is ensured by a ℤ5 discrete symmetry, through which the DM annihilation rate is dominated by the 3 → 2 self-annihilating processes. The right amount of thermal relic abundance can be obtained with perturbative couplings in the resonant SIMP scenario, while the astrophysical bounds inferred from the Bullet cluster and spherical halo shapes can be satisfied. We show that SIMP DM is able to maintain kinetic equilibrium with thermal plasma until the freeze-out temperature via the Yukawa interactions associated with neutrino mass generation.

    DOI: 10.1007/JHEP07(2017)101

    Repository Public URL: http://hdl.handle.net/2324/4797815

  • Toward background-free RENP using a photonic crystal waveguide Reviewed

    Minoru Tanaka, Koji Tsumura, Noboru Sasao, Motohiko Yoshimura

    Progress of Theoretical and Experimental Physics   2017 ( 4 )   2017.4

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    We study how to suppress multiphoton emission background in QED against radiative emission of a neutrino pair (RENP) from atoms. We pursue the possibility of background suppression using the photonic band structure of periodic dielectric media, called photonic crystals. The modification of photon emission rate in photonic crystal waveguides is quantitatively examined to clarify the condition of background-free RENP.

    DOI: 10.1093/ptep/ptx035

    Repository Public URL: http://hdl.handle.net/2324/4797814

  • Gravitational wave from dark sector with dark pion Reviewed

    Koji Tsumura, Masatoshi Yamada, Yuya Yamaguchi

    Journal of Cosmology and Astroparticle Physics   2017 ( 7 )   2017.1

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    In this work, we investigate the spectra of gravitational waves produced by chiral symmetry breaking in dark quantum chromodynamics (dQCD) sector. The dark pion (π) can be a dark matter candidate as weakly interacting massive particle (WIMP) or strongly interacting massive particle (SIMP). For a WIMP scenario, we introduce the dQCD sector coupled to the standard model (SM) sector with classical scale invariance and investigate the annihilation process of the dark pion via the 2π 2 SM process. For a SIMP scenario, we investigate the 3π 2π annihilation process of the dark pion as a SIMP using chiral perturbation theory. We find that in the WIMP scenario the gravitational wave background spectra can be observed by future space gravitational wave antennas. On the other hand, when the dark pion is the SIMP dark matter with the constraints for the chiral perturbative limit and pion-pion scattering cross section, the chiral phase transition becomes crossover and then the gravitational waves are not produced.

    DOI: 10.1088/1475-7516/2017/07/044

    Repository Public URL: http://hdl.handle.net/2324/4797813

  • Reheating era leptogenesis in models with a seesaw mechanism Reviewed

    Yuta Hamada, Koji Tsumura, Daiki Yasuhara

    Physical Review D   95 ( 10 )   2017.1

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    Observed baryon asymmetry can be achieved not only by the decay of right-handed neutrinos but also by the scattering processes in the reheating era. In the latter scenario, new physics in high energy scale does not need to be specified, but only two types of the higher dimensional operator of the standard model particles are assumed in the previous work. In this paper, we examine the origin of the higher dimensional operators assuming models with a certain seesaw mechanism at the high energy scale. The seesaw mechanism seems to be a simple realization of the reheating era leptogenesis because the lepton number violating interaction is included. We show that the effective interaction giving CP violating phases is provided in the several types of models and also the reheating era leptogenesis actually works in such models. Additionally, we discuss a possibility for lowering the reheating temperature in the radiative seesaw models, where the large Yukawa coupling is naturally realized.

    DOI: 10.1103/PhysRevD.95.103505

    Repository Public URL: http://hdl.handle.net/2324/4797806

  • Systematic U(1)B-L Extensions of Loop-Induced Neutrino Mass Models with Dark Matter Reviewed

    Shu Yu Ho, Takashi Toma, Koji Tsumura

    Physical Review D   94 ( 3 )   2016.8

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    We study the gauged U(1)B-L extensions of the models for neutrino masses and dark matter. In this class of models, tiny neutrino masses are radiatively induced through the loop diagrams, while the origin of the dark matter stability is guaranteed by the remnant of the gauge symmetry. Depending on how the lepton number conservation is violated, these models are systematically classified. We present complete lists for the one-loop Z2 and the two-loop Z3 radiative seesaw models as examples of the classification. The anomaly cancellation conditions in these models are also discussed.

    DOI: 10.1103/PhysRevD.94.033007

    Repository Public URL: http://hdl.handle.net/2324/4797805

  • Models of the LHC diphoton excesses valid up to the Planck scale Reviewed

    Yuta Hamada, Hikaru Kawai, Kiyoharu Kawana, Koji Tsumura

    Physical Review D   94 ( 1 )   2016.7

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    We discuss a possibility to explain the LHC diphoton excesses at 750 GeV by the new scalar X that couples to the gauge bosons through the loop of new massive particles with standard model charges. We assume that the new particles decay into the standard model particles at the tree level. We systematically examine the models that preserve the vacuum stability and the perturbativity up to the Planck scale. When we take scalars for the new particles, we find that only a few diquark and dilepton models can explain the observed diphoton cross section without conflicting the experimental mass bounds. When we take vectorlike fermions for the new particles, we find rather different situations depending on whether their couplings to X are scalar or pseudoscalar type. In the former case, a few models are allowed if we introduce only one species of fermions. The more fermions we introduce, the more models are allowed. In the latter case, most of the models are allowed because of the large coupling between X and photon. It is interesting that the allowed mass regions of the scalar particles might be reached by the next lepton colliders.

    DOI: 10.1103/PhysRevD.94.014007

    Repository Public URL: http://hdl.handle.net/2324/4796031

  • Survey of Higgs interpretations of the diboson excesses Reviewed

    Yuji Omura, Kazuhiro Tobe, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   92 ( 5 )   2015.9

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    We investigate diboson signals in the standard model (SM) with an extended Higgs sector, motivated by the excesses in the diboson channels at the LHC. We begin with the unitarity sum rules of the weak gauge boson scattering assuming the Higgs sector is extended. According to the sum rules, we discuss the Higgs interpretations of the diboson signals and the consistency with the ATLAS diboson anomaly and other experimental constraints. As a concrete example, we propose a two-Higgs-doublet model where the Yukawa coupling of an extra CP-even scalar with up-type quark is relatively large. The diboson (WW and ZZ) signals can be explained by 2 TeV CP-even Higgs boson, while the partners, the CP-odd and the charged Higgs bosons in the extra doublet, are severely constrained by both the LHC direct search and the indirect search via flavor observables. Especially, in order to avoid the diboson resonance search in the Vh channel, further extensions of the model are required. The diboson excess is correlated with the SM Higgs signals in our framework, so that the precise measurement of the SM Higgs boson is also important to test the Higgs interpretation.

    DOI: 10.1103/PhysRevD.92.055015

    Repository Public URL: http://hdl.handle.net/2324/4796030

  • Properties and searches of the exotic neutral Higgs bosons in the Georgi-Machacek model Reviewed

    Cheng Wei Chiang, Koji Tsumura

    Journal of High Energy Physics   2015 ( 4 )   2015.4

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    Abstract: The Georgi-Machacek model predicts the existence of four neutral Higgs bosons, one of which can be identified as the 125-GeV Higgs boson. The latest Higgs data favor the parameter space of small mixing angle α between the two custodial singlets of the model. The other two neutral Higgs bosons belong respectively to the custodial triplet and quintet. We study the general decay and production properties of these particles in the small-α scenario. Constraints on the SU(2)L triplet vacuum expectation value are obtained as a function of the exotic Higgs boson masses using latest ATLAS data of various search channels for additional neutral Higgs bosons.

    DOI: 10.1007/JHEP04(2015)113

    Repository Public URL: http://hdl.handle.net/2324/4795978

  • Does unitarity imply finiteness of electroweak oblique corrections at one loop? Constraining extra neutral Higgs bosons Reviewed

    Ryo Nagai, Masaharu Tanabashi, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   91 ( 3 )   2015.2

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    Introducing an arbitrary number of neutral Higgs bosons in the electroweak symmetry breaking sector, we derive a set of conditions among Higgs couplings which need to be satisfied to maintain the unitarity of the high energy scattering amplitudes of weak gauge bosons at the tree level (unitarity sum rules). It is shown that the unitarity sum rules require the tree level ρ parameter to be 1, without explicitly invoking the custodial symmetry arguments. The one loop finiteness of the electroweak oblique corrections is automatically guaranteed once these unitarity sum rules are imposed among Higgs couplings. Severe constraints on the lightest Higgs coupling (125 GeV Higgs coupling) and the mass of the second lightest Higgs boson are obtained from the unitarity and the results of the electroweak precision tests (oblique parameter measurements). These results are compared with the effective theory of the light Higgs boson, and we find simple relationships between the mass of the second lightest Higgs boson in our framework and the ultraviolet cutoff in the effective theory framework.

    DOI: 10.1103/PhysRevD.91.034030

    Repository Public URL: http://hdl.handle.net/2324/4796029

  • Discrimination of models including doubly charged scalar bosons using tau decays Reviewed

    Koji Tsumura

    Nuclear Physics B - Proceedings Supplements   253-255   230 - 231   2014.10

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    The doubly charged scalar boson (H±±) is introduced in several models of the new physics beyond the standard model. The H±± has Yukawa interactions with two left-handed charged leptons or two right-handed charged leptons depending on the models. We study kinematical properties of H±± decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of its decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the H±± decay products.

    DOI: 10.1016/j.nuclphysbps.2014.09.063

    Repository Public URL: http://hdl.handle.net/2324/4795977

  • QCD corrections to quark (chromo)electric dipole moments in high-scale supersymmetry Reviewed

    Kaori Fuyuto, Junji Hisano, Natsumi Nagata, Koji Tsumura

    Journal of High Energy Physics   2013 ( 12 )   2013.12

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    Recent results from the LHC experiments, both for the Higgs mass measurement and the direct search for supersymmetric (SUSY) particles, might indicate that the SUSY breaking scale is much higher than the electroweak scale. Although it is difficult to investigate such a scenario at collider experiments, the measurement of the hadronic electric dipole moments is one of promising ways to detect the effects of the SUSY particles. These effects are expressed in terms of the CP-violating effective operators defined at the SUSY breaking scale, which involve quarks, gluons, photons, and gluinos. In this paper, we discuss the QCD corrections to the effective operators in the high-scale SUSY scenario. To appropriately evaluate the radiative corrections in the presence of large mass hierarchy among the SUSY particles, we exploit an effective theoretical approach based on the renormalization-group equations. As a result, it is found that the low-energy quark electric and chromoelectric dipole moments may differ from those evaluated in previous works by O (100) % and O (10) %, respectively.

    DOI: 10.1007/JHEP12(2013)010

    Repository Public URL: http://hdl.handle.net/2324/4795987

  • Determination of tanâ¡β from the Higgs boson decay at linear colliders Reviewed

    Shinya Kanemura, Koji Tsumura, Hiroshi Yokoya

    Physical Review D - Particles, Fields, Gravitation and Cosmology   88 ( 5 )   2013.9

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    In the two Higgs doublet models, tanâ¡β is an important parameter, which is defined as the ratio of the vacuum expectation values of the doublets. We study how accurately tanâ¡β can be determined at linear colliders via the precision measurement of the decay branching fraction of the standard model (SM)-like Higgs boson. Since the effective coupling constants of the Higgs boson with the weak gauge bosons are expected to be measured accurately, the branching ratios can be precisely determined. Consequently, tanâ¡β can be determined with a certain amount of accuracy. Comparing the method to those using direct production of the additional Higgs bosons, we find that, depending on the type of Yukawa interactions, the precision measurement of the decay of the SM-like Higgs boson can be the best way to determine tanâ¡β, when the deviations in the coupling constants with the gauge boson from the SM prediction are observed at linear colliders.

    DOI: 10.1103/PhysRevD.88.055010

    Repository Public URL: http://hdl.handle.net/2324/4795985

  • Discrimination of models including H ±± by using tau decay Reviewed

    Koji Tsumura

    23rd Hadron Collider Physics Symposium 2012, HCP 2012 EPJ Web of Conferences   49   2013.9

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    The doubly charged scalar boson (H±±) is introduced in several models of the new physics beyond the standard model. The H±± can have Yukawa interactions with two left-handed charged leptons or two righthanded charged leptons. We study kinematical properties of H±± decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of the tau decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the H ±± decay products [1].

    DOI: 10.1051/epjconf/20134918004

    Repository Public URL: http://hdl.handle.net/2324/4795982

  • Feasibility study of the measurement of Higgs pair creation at a photon linear collider Reviewed

    Shin Ichi Kawada, Nozomi Maeda, Tohru Takahashi, Katsumasa Ikematsu, Keisuke Fujii, Yoshimasa Kurihara, Koji Tsumura, Daisuke Harada, Shinya Kanemura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   85 ( 11 )   2012.6

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    We studied the feasibility of the measurement of Higgs pair creation at a photon linear collider. From the sensitivity to the anomalous self-coupling of the Higgs boson, the optimum γγ collision energy was found to be around 270 GeV for a Higgs mass of 120GeV/c2. We found that large backgrounds such as γγ→W +W -, ZZ, and bb̄bb̄ can be suppressed if correct assignment of tracks to parent partons is achieved and Higgs pair events can be observed with a statistical significance of ∼5σ by operating the photon linear collider for 5 years.

    DOI: 10.1103/PhysRevD.85.113009

    Repository Public URL: http://hdl.handle.net/2324/4795785

  • Multi-τ signatures at the LHC in the two Higgs doublet model Reviewed

    Shinya Kanemura, Koji Tsumura, Hiroshi Yokoya

    Physical Review D - Particles, Fields, Gravitation and Cosmology   85 ( 9 )   2012.5

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    A detailed simulation study is performed for multi-τ signatures at the Large Hadron Collider, which can be used to probe additional Higgs bosons with lepton-specific Yukawa interactions. We here consider the two Higgs doublet model with the Type-X Yukawa interaction, where nonstandard Higgs bosons predominantly decay into tau leptons. These extra Higgs bosons can be pair produced at hadron colliders. Consequently, multi-τ originated signals appear in the final state as a promising signature of such a model. We find that the main background can be considerably reduced by requiring the high multiplicity of leptons and tau-jets with appropriate kinematical cuts in the final state. Thus, assuming the integrated luminosity of a hundred of inverse fb, the excess can be seen in various three- and four-lepton channels. With the integrated luminosity of thousands of inverse fb, the determination of the mass as well as ratios of leptonic decay branching ratios of these Higgs bosons would also be possible.

    DOI: 10.1103/PhysRevD.85.095001

    Repository Public URL: http://hdl.handle.net/2324/4795784

  • Higgs quadruplet for the type III seesaw model and implications for μ→eγ and μ-e conversion Reviewed

    Bo Ren, Koji Tsumura, Xiao Gang He

    Physical Review D - Particles, Fields, Gravitation and Cosmology   84 ( 7 )   2011.10

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    In the type III seesaw model, the heavy neutrinos are contained in leptonic triplet representations. The Yukawa couplings of the triplet fermion and the left-handed neutrinos with the doublet Higgs field produce the Dirac mass terms. Together with the Majorana masses for the leptonic triplets, the light neutrinos obtain nonzero seesaw masses. We point out that it is also possible to have a quadruplet Higgs field to produce the Dirac mass terms to facilitate the seesaw mechanism. The vacuum expectation value of the quadruplet Higgs is constrained to be small by electroweak precision data. Therefore, the Yukawa couplings of a quadruplet can be much larger than those for a doublet. We also find that unlike the usual type III seesaw model where at least two copies of leptonic triplets are needed, with both doublet and quadruplet Higgs representations, just one leptonic triplet is possible to have a phenomenologically acceptable model because light neutrino masses can receive sizable contributions at both tree and one-loop levels. Large Yukawa couplings of the quadruplet can induce observable effects for lepton flavor violating processes μ→eγ and μ-e conversion. Implications of the recent μ→eγ limit from MEG and the limit on μ-e conversion on Au are also given. Some interesting collider signatures for the doubly charged Higgs boson in the quadruplet are discussed.

    DOI: 10.1103/PhysRevD.84.073004

    Repository Public URL: http://hdl.handle.net/2324/4795782

  • μ-e conversion with four generations Reviewed

    N. G. Deshpande, T. Enkhbat, T. Fukuyama, X. G. He, L. H. Tsai, K. Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   703 ( 5 )   562 - 566   2011.9

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    We study μ-e conversion with sequential four generations. A large mass for the fourth generation neutrino can enhance the conversion rate by orders of magnitude. We compare constraints obtained from μ-e conversion using experimental bounds on various nuclei with those from μ→eγ and μ→eēe. We find that the current bound from μ-e conversion with Au puts the most stringent constraint in this model. The relevant flavor changing parameter λ;μe=V*4μVe4 is constrained to be less than 1.6×10-5 for the fourth generation neutrino mass larger than 100 GeV. Implications for future μ-e conversion, μ→eγ and μ→eēe experiments are discussed.

    DOI: 10.1016/j.physletb.2011.08.045

    Repository Public URL: http://hdl.handle.net/2324/4795780

  • Phenomenology in the Zee model with the A4 symmetry Reviewed

    Takeshi Fukuyama, Hiroaki Sugiyama, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   83 ( 5 )   2011.3

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    The Zee model generates neutrino masses at the one-loop level by adding charged SU(2)L-singlet and extra SU(2)L-doublet scalars to the standard model of particle physics. We introduce the softly broken A 4 symmetry to the Zee model as the origin of the nontrivial structure of the lepton flavor mixing. This model is compatible with the tribimaximal mixing which agrees well with neutrino oscillation measurements. Then, a sum rule m1eiα12+2m2+3m3eiα 32=0 is obtained and it results in Δm312<0 and m3 ≥1.8×10-2eV. The effective mass |(Mν) ee| for the neutrinoless double beta decay is predicted as |(M ν)ee|≥1.7×10-2eV. The characteristic particles in this model are SU(2)L-singlet charged Higgs bosons sα+(α=ξ,η,ζ) which are made from a 3 representation of A4. Contributions of sα± to the lepton flavor violating decays of charged leptons are almost forbidden by an approximately remaining Z3 symmetry; only BR(τ→ēμ μ) can be sizable by the flavor changing neutral current interaction with SU(2)L-doublet scalars. Therefore, sα± can easily be light enough to be discovered at the LHC with satisfying current constraints. The flavor structures of BR(sα-→ℓν) are also discussed.

    DOI: 10.1103/PhysRevD.83.056016

    Repository Public URL: http://hdl.handle.net/2324/4795562

  • Higgs boson pair production in new physics models at hadron, lepton, and photon colliders Reviewed

    K. Tsumura

    Nuovo Cimento della Societa Italiana di Fisica C   34 ( SUPP1 )   77 - 84   2011.1

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    We discuss Higgs boson pair production processes at future hadron and lepton colliders including the photon collision option in several new physics models, i.e. the two-Higgs-doublet model, the scalar leptoquark model, the sequential fourth-generation fermion model and the vectorlike quark model. Cross sections for these processes can differ significantly from the standard model predictions, due to the nondecoupling effect in the triple Higgs boson coupling constant. For the one-loop induced processes such as gg → hh and γγ → hh, new physics particles can mediate in a loop diagram, which can affect cross sections. Measurements of the Higgs boson pair production processes can be useful not only to test the standard model but also to explore new physics models.

    DOI: 10.1393/ncc/i2011-11007-8

    Repository Public URL: http://hdl.handle.net/2324/4795561

  • ν-Two Higgs doublet model and its collider phenomenology Reviewed

    Naoyuki Haba, Koji Tsumura

    Journal of High Energy Physics   2011 ( 6 )   2011.1

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    Smallness of neutrino masses can be explained by introducing a tiny vacuum expectation value of an extra-Higgs doublet which couples to right-handed neutrinos (NR). This situation is naturally realized in ν-Two Higgs Doublet Model (νTHDM), where a TeV-scale seesaw mechanism can work well. We investigate observable phenomenology of νTHDM at LHC and ILC experiments. Charged Higgs boson (H±) in νTHDM is almost originated from the extra-Higgs doublet and its coupling strength to neutrinos are not small. Then this model induces rich phenomenology at the LHC, for example, when m H± > MN, observable charged tracks can be induced from long lived charged Higgs. On the other hand, when mH ± < MN, right-handed neutrinos can be long-lived, and secondary vertices may be tagged at the LHC. The νTHDM also predicts observable lepton number violating process at the ILC.

    DOI: 10.1007/JHEP06(2011)068

    Repository Public URL: http://hdl.handle.net/2324/4795560

  • Phenomenology in the Higgs triplet model with the A4 symmetry Reviewed

    Takeshi Fukuyama, Hiroaki Sugiyama, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   82 ( 3 )   2010.8

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    We discuss the phenomenology of doubly and singly charged Higgs bosons [of SU(2)L-triplet fields] in the simplest A4-symmetric version of the Higgs triplet model. Mass eigenstates of these Higgs bosons are obtained explicitly from the Higgs potential. It is shown that their decays into a pair of leptons have unique flavor structures which can be tested at the LHC if some of their masses are below the TeV scale. Sizable decay rates for τ→μ̄ee and τ→ēμμ can be obtained naturally, while other τ→̄′′′, μ→ēee, and →γ, are almost forbidden in this model. Contributions of these Higgs bosons to the nonstandard interactions of neutrinos are also considered.

    DOI: 10.1103/PhysRevD.82.036004

    Repository Public URL: http://hdl.handle.net/2324/4795557

  • Phenomenology of flavon fields at the LHC Reviewed

    Koji Tsumura, Liliana Velasco-Sevilla

    Physical Review D - Particles, Fields, Gravitation and Cosmology   81 ( 3 )   2010.2

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    We study low energy constraints from flavor violating processes, production, and decay at the LHC of a scalar field φ (flavon) associated to the breaking of a nonsupersymmetric Abelian family symmetry at the TeV scale. This symmetry is constrained to reproduce fermion masses and mixing, up to O(1) coefficients. The nonsupersymmetric gauged U(1) models considered are severely restricted by cancellation of anomalies and LEP bounds on contact interactions; consequently its phenomenology is out of the LHC reach. We therefore introduce an effective U(1) which is not gauged and is broken explicitly by a CP-odd term at the TeV scale. This helps us to explore flavor violating processes, production, and decay at the LHC for these kind of light scalars. In this context we first study the constraints on the flavon mass and its vacuum expectation value from low energy flavor changing processes such as μ→eγ. We find that a flavon of about mφ 150GeV could be experimentally allowed. These kinds of flavons could be significantly generated at the LHC via the gluon fusion mechanism and the single top production channel gu→tφ. The produced flavons can have characteristic decay modes such as tc̄ for mφ mt, and τμ̄ for mφ mt, which could be effectively useful to detect flavons.

    DOI: 10.1103/PhysRevD.81.036012

    Repository Public URL: http://hdl.handle.net/2324/4795556

  • Constraints from LFV processes in the Higgs Triplet Model Reviewed

    Takeshi Fukuyama, Hiroaki Sugiyama, Koji Tsumura

    Journal of High Energy Physics   2010 ( 3 )   2010.1

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    Constraints from lepton flavor violating processes are translated into lower bounds on vΔmH±± in the Higgs Triplet Model by considering correlations through the neutrino mass matrix. It is shown that μ → eγ, rare τ decays (especially, τ → μ̄ee), and the muonium conversion can give a more stringent bound on vΔlmH± ± in some parameter regions than the bound from μ → ēee which is expected naively to give the most stringent one. We consider the cases of suppressed μ → ēee not only for CP-conserving sets of phases but also for arbitrary values.

    DOI: 10.1007/JHEP03(2010)044

    Repository Public URL: http://hdl.handle.net/2324/4795555

  • Lepton flavour violation at an electron-photon collider Reviewed

    K. Tsumura

    Nuovo Cimento della Societa Italiana di Fisica C   33 ( 2 )   103 - 108   2010.1

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    We study the LFV Higgs production processes e-γ → ℓ- φ (ℓ = μ, τ; φ = H, A) as a probe of Higgs-mediated LFV couplings at an electron-photon collider, where H and A are extra CP even and odd Higgs bosons, respectively, in the two Higgs doublet model. Under the constraints from the current data of muon and tau rare decay, the cross-section can be significantly large. It would improve the experimental upper bounds on the effective LFV coupling constants. In addition, the chirality nature of the LFV Higgs coupling constants can be measured by selecting electron beam polarizations. PACS 12.15. Ji - Applications of electroweak models to specific processes. PACS 12.60.Fr - Extensions of electroweak Higgs sector. PACS 14.60.-z - Leptons. PACS 14.60.Fg-Taus.

    DOI: 10.1393/ncc/i2010-10597-9

    Repository Public URL: http://hdl.handle.net/2324/4795552

  • Effects of the anomalous Higgs couplings on the Higgs boson production at the Large Hadron Collider Reviewed

    Shinya Kanemura, Koji Tsumura

    European Physical Journal C   63 ( 1 )   11 - 21   2009.9

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    We study the impact of dimension-six operators on single- and double-Higgs production rates via gluon fusion at the Large Hadron Collider (LHC). If the top-Yukawa coupling is modified by some new physics whose scale is of the TeV scale, its effect changes the cross sections of single-Higgs production gg→H and double-Higgs production gg→HH through the top-loop diagram. In particular, double-Higgs production can receive significant enhancement from the effective top-Yukawa coupling and the new dimension-five coupling which are induced by the dimension-six operator. Comparing these results to the forthcoming data at the LHC, one can extract information of the dimension-six operators relevant to the top quark and the Higgs boson.

    DOI: 10.1140/epjc/s10052-009-1077-0

    Repository Public URL: http://hdl.handle.net/2324/4795551

  • A powerful tool for measuring Higgs boson associated lepton flavour violation Reviewed

    Shinya Kanemura, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   674 ( 4-5 )   295 - 298   2009.4

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    In models with extended Higgs sectors, Higgs-boson-mediated Lepton Flavour Violation (LFV) can naturally appear. We study the physics potential of an electron-photon collider on searching LFV processes e- γ → ℓ- φ (ℓ = μ, τ; φ = H, A) where H and A are extra CP even and odd Higgs bosons, respectively, in the minimal supersymmetric standard model and the effective two Higgs doublet model. The production cross section can be significantly large for the maximal allowed values of the LFV coupling constants under the current experimental data. Present experimental upper bounds on the effective LFV coupling constants would be considerably improved by searching these processes, which would be better than MEG and COMET experiments and also those at LHCb and SuperKEKB. Moreover, one can separately measure chirality of effective LFV coupling constants via these processes by selecting electron polarizations.

    DOI: 10.1016/j.physletb.2009.03.041

    Repository Public URL: http://hdl.handle.net/2324/4795520

  • Higgs boson pair production at a photon-photon collision in the two Higgs doublet model Reviewed

    Eri Asakawa, Daisuke Harada, Shinya Kanemura, Yasuhiro Okada, Koji Tsumura

    Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics   672 ( 4-5 )   354 - 360   2009.3

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    We calculate the cross section of Higgs boson pair production at a photon collider in the two Higgs doublet model. We focus on the scenario in which the lightest CP even Higgs boson (h) has the Standard Model like couplings to the gauge bosons. We take into account the one-loop correction to the hhh coupling as well as additional one-loop diagrams due to charged Higgs bosons to the γ γ → h h helicity amplitudes. It is found that the full cross section can be enhanced by both these effects to a considerable level. We discuss the impact of these corrections on the hhh coupling measurement at the photon collider.

    DOI: 10.1016/j.physletb.2009.01.050

    Repository Public URL: http://hdl.handle.net/2324/4795522

  • CP violation due to multi-Froggatt-Nielsen fields Reviewed

    Shinya Kanemura, Koichi Matsuda, Toshihiko Ota, Serguey Petcov, Tetsuo Shindou, Eiichi Takasugi, Koji Tsumura

    European Physical Journal C   51 ( 4 )   927 - 931   2007.8

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    We study how to incorporate CP violation in the Froggatt-Nielsen (FN) mechanism. To this end, we introduce non-renormalizable interactions with a flavor democratic structure to the fermion mass generation sector. It is found that at least two iso-singlet scalar fields with a discrete symmetry imposed are necessary to generate CP violation due to the appearance of the relative phase between their vacuum expectation values. In the simplest model, the ratios of quark masses and the Cabibbo-Kobayashi-Maskawa (CKM) matrix including the CP violating phase are determined by the CKM element |Vus| and the ratio of two vacuum expectation values of FN fields, R=|R|e (a magnitude and a phase). It is demonstrated how the angles φi (i=1,...,3) of the unitarity triangle and the CKM off-diagonal elements |V ub| and |Vcb| are predicted as a function of |V us|, |R| and α. Although the predicted value of the CP violating phase does not agree with the experimental data within the simplest model, the basic idea of our scenario would be promising if one wants to construct a more realistic model of flavor and CP violation.

    DOI: 10.1140/epjc/s10052-007-0343-2

    Repository Public URL: http://hdl.handle.net/2324/4795159

  • Dimension-six top-quark Higgs-boson interaction and its effect in collider phenomenology Reviewed

    Shinya Kanemura, Daisuke Nomura, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   74 ( 7 )   2006.11

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    Measurement of the Yukawa interaction between the top quark and the Higgs boson should be useful to clarify the mechanism of fermion mass generation. We discuss the impact of nonstandard interactions characterized by dimension-six operators on the effective top Yukawa coupling. The cross section of the process e-e+→W-W+νν̄→tt̄νν̄ is calculated including these operators, and possible deviation from the standard model prediction is evaluated under the constraint from perturbative unitarity and current experimental data. We find that if the new physics scale is in a TeV region, the cross section can be significantly enhanced due to the nonstandard interactions. Such a large effect should be detectable at the International Linear Collider.

    DOI: 10.1103/PhysRevD.74.076007

    Repository Public URL: http://hdl.handle.net/2324/4795154

  • Bi-maximal mixing at GUT, the low energy data and the leptogenesis Reviewed

    S. Kanemura, K. Matsuda, H. Nakano, T. Ota, T. Shindou, E. Takasugi, K. Tsumura

    Nuclear Physics B - Proceedings Supplements   149   357 - 359   2005.12

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    In the framework of the minimum supersymmetric model with right-handed neutrinos, we consider the Bi-maximal mixing which is realized at the GUT scale and discuss a question that this model can reproduce the low energy phenomena and the leptogenesis.

    DOI: 10.1016/j.nuclphysbps.2005.05.067

    Repository Public URL: http://hdl.handle.net/2324/4795143

  • Yukawa matrix for the neutrino and Lepton Flavour Violation Reviewed

    S. Kanemura, K. Matsuda, T. Ota, T. Shindou, E. Takasugi, K. Tsumura

    Nuclear Physics B - Proceedings Supplements   149   360 - 362   2005.12

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    We estimate the magnitude of Lepton Flavour Violation (LFV) from the phase of the neutrino Yukawa matrix. In the minimal supersymmetric standard model with right-handed neutrinos, the LFV processes li → l can appear through the slepton mixing, which comes from the renormalization group effect on the right-handed neutrino Yukawa interaction between the Grand Unified Theory scale and the heavy right-handed neutrino mass scale. Two types of phases exist in the neutrino Yukawa matrix. One is the Majorana phase, which can change the magnitude of the LFV branching ratios by a few factor. The other phases relate for the size of the Yukawa hierarchy and its phase effect can change the LFV branching ratios by several orders of magnitude.

    DOI: 10.1016/j.nuclphysbps.2005.05.068

    Repository Public URL: http://hdl.handle.net/2324/4795142

  • Enhancement of lepton flavor violation in a model with bimaximal mixing at the grand unification scale Reviewed

    Shinya Kanemura, Koichi Matsuda, Toshihiko Ota, Tetsuo Shindou, Eiichi Takasugi, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   72 ( 9 )   2005.11

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    We study phenomenological predictions in the scenario with the quasidegenerate relation among neutrino Dirac masses, mD1mD2<mD3, assuming the bimaximal mixing at the grand unification scale in supersymmetric standard models with right-handed neutrinos. A sufficient lepton number asymmetry can be produced for successful leptogenesis. The lepton flavor violating process μ→eγ can be enhanced due to the Majorana phase, so that it can be detectable at forthcoming experiments. The processes τ→eγ and τ→μγ are suppressed because of the structure of neutrino Dirac masses, and their branching ratios are smaller than that of μ→eγ.

    DOI: 10.1103/PhysRevD.72.093004

    Repository Public URL: http://hdl.handle.net/2324/4795141

  • Phase effects from the general neutrino Yukawa matrix on lepton flavor violation Reviewed

    Shinya Kanemura, Koichi Matsuda, Toshihiko Ota, Tetsuo Shindou, Eiichi Takasugi, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   72 ( 5 )   2005.9

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    We examine contributions from Majorana phases to lepton flavor violating processes in the framework of the minimal supersymmetric standard model with heavy right-handed neutrinos. All phases in the complex neutrino Yukawa matrix are taken into account in our study. We find that in the scenario with universal soft-breaking terms sizable phase effects can appear on the lepton flavor violating processes such as μ→eγ, τ→eγ, and τ→μγ. In particular, the branching ratio of μ→eγ can be considerably enhanced due to the Majorana phases, so that it can be much greater than that of τ→μγ.

    DOI: 10.1103/PhysRevD.72.055012

    Repository Public URL: http://hdl.handle.net/2324/4795140

  • Erratum Phase effects from the general neutrino Yukawa matrix on lepton flavor violation (Physical Review D - Particles, Fields, Gravitation and Cosmology (2005) 72 (055012)) Reviewed

    Shinya Kanemura, Koichi Matsuda, Toshihiko Ota, Tetsuo Shindou, Eiichi Takasugi, Koji Tsumura

    Physical Review D - Particles, Fields, Gravitation and Cosmology   72 ( 5 )   2005.9

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    DOI: 10.1103/PhysRevD.72.059904

    Repository Public URL: https://hdl.handle.net/2324/4795140

  • Phase contribution to LFV Reviewed

    S. Kanemura, K. Matsuda, T. Ota, T. Shindou, E. Takasugi, K. Tsumura

    Nuclear Physics B - Proceedings Supplements   143 ( 1-3 SPEC. ISS. )   2005.6

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    DOI: 10.1016/j.nuclphysbps.2005.01.189

    Repository Public URL: http://hdl.handle.net/2324/4795139

  • Radiative corrections of neutrino mass matrix and lepton flavor violation processes Reviewed

    S. Kanemura, K. Matsuda, T. Ota, T. Shindou, E. Takasugi, K. Tsumura

    Nuclear Physics B - Proceedings Supplements   143 ( 1-3 SPEC. ISS. )   2005.6

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.nuclphysbps.2005.01.186

    Repository Public URL: http://hdl.handle.net/2324/4795138

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Presentations

  • ILCの物理へのインパクト Invited

    津村浩二

    日本物理学会 2018年 秋季大会 素粒子実験-素粒子論領域合同シンポジウム  2018.9 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

    Venue:長野   Country:Japan  

  • Lepton Flavor Violation in the Lepton Sector Invited International conference

    Koji Tsumura

    Lepton Flavor Violation in the Lepton Sector  2017.6 

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    Event date: 2017.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Prague  

  • Prospects of LHC Run II Invited International conference

    Koji Tsumura

    Developments in String Theory and Quantum Field Theory  2015.11 

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    Event date: 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • Higgs物理でHL-LHCに期待すること Invited

    津村浩二

    日本物理学会 2014年 秋季大会 素粒子実験-素粒子論領域合同シンポジウム  2014.9 

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    Event date: 2014.9

    Language:Japanese   Presentation type:Symposium, workshop panel (public)  

    Venue:佐賀   Country:Japan  

  • Physics at ILC : A Theory Perspective Invited International conference

    Koji Tsumura

    ILD Meeting 2014  2014.9 

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    Event date: 2014.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Iwate   Country:Japan  

  • ILC Physics Overview Invited International conference

    Koji Tsumura

    ILC Tokusui Workshop 2013  2013.12 

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    Event date: 2013.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • The origin of pseudo-Nabmu-Goldstone-Boson Dark Matter Invited International conference

    Koji Tsumura

    Hokkaido Workshop on Particle Physics at Crossroads  2024.3 

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    Event date: 2024.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hokkaido University   Country:Japan  

  • 安定な擬南部ゴールドストン暗黒物質の起源

    津村浩二

    第129回日本物理学会九州支部例会  2023.12 

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    Event date: 2023.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:長崎大学   Country:Japan  

  • New View of Particle Physics from Neutrinos and Phenomena Beyond the Standard Model International conference

    Koji Tsumura

    International Conference on the Physics of the Two Infinities  2023.3 

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    Event date: 2023.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto University   Country:Japan  

  • 粒子数非保存の模型 Invited

    津村浩二

    原子核によるバリオン数・レプトン数の物理  2023.3 

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    Event date: 2023.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪大学 核物理研究センター   Country:Japan  

  • Generalized Higgs effective field theory and its applications Invited International conference

    Koji Tsumura

    The 5th KMI International Symposium on “Quest for the Origin of Particles and the Universe”  2023.2 

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    Event date: 2023.2

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Nagoya University   Country:Japan  

  • The origin of pseudo-Nambu-Goldstone Dark Matter' Invited

    津村浩二

    Kagoshima Workshop on Particles, Fields and Strings 2023  2023.2 

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    Event date: 2023.2

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:鹿児島市   Country:Japan  

  • The origin of pseudo-Nabmu-Goldstone-Boson Dark Matter Invited International conference

    Koji Tsumura

    2022 NTU-Kyoto high energy physics workshop/Kawai Fest  2022.12 

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    Event date: 2022.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:National Taiwan University   Country:Japan  

  • 暗黒SU(2)にもとづく擬南部ゴールドストン暗黒物質模型

    津村浩二

    第128回日本物理学会九州支部例会  2022.12 

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    Event date: 2022.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:熊本大学   Country:Japan  

  • The origin of pseudo-Nabmu-Goldstone-Boson Dark Matter Invited International conference

    Koji Tsumura

    KEK Theory Meeting on Particle Physics Phenomenology (KEK-PH2022) and International Joint Workshop on the Standard Model and beyond  2022.11 

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    Event date: 2022.11 - 2022.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:KEK   Country:Japan  

  • 擬南部ゴールドストン暗黒物質と暗黒SU(2)

    津村浩二

    瀬戸内サマーインスティテュート2022  2022.9 

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    Event date: 2022.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:広島大学   Country:Japan  

  • ヒッグス物理の理解はどこまで進んだか? Invited

    津村浩二

    日本物理学会 2022年 秋季大会 素粒子論-素粒子実験領域合同  2022.9 

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    Event date: 2022.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:岡山理科大学   Country:Japan  

  • ヒッグス物理の深化 Invited

    津村浩二

    次世代エネルギーフロンティア実験の検討会  2022.8 

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    Event date: 2022.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:湯河原市   Country:Japan  

  • 擬南部ゴールドストン暗黒物質と大統一理論

    津村浩二

    第127回日本物理学会九州支部例会  2021.12 

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    Event date: 2021.12

    Language:Japanese  

    Country:Japan  

  • PQ機構としてのバリオン数の破れ

    津村浩二

    素粒子物理学の進展2021  2021.9 

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    Event date: 2021.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:オンライン   Country:Japan  

  • Pseudo-Nambu-Goldstone Dark Matter from Grand Unified Theory Invited International conference

    Koji Tsumura

    The 7th Quantum Science (QS) symposium -The main symposium of ICCMSE 2021-Computational Chemistry and Computational Physics  2021.9 

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    Event date: 2021.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:オンライン   Country:Japan  

  • C02報告 Invited

    津村浩二

    新学術成果報告研究会  2020.4 

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    Event date: 2020.4

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  • The Origin of Pseudo-Nambu-Goldstone Dark Matter Invited International conference

    Koji Tsumura

    RIS-TCS 2020 -Frontier of Physics and Chemistry-  2020.3 

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    Event date: 2020.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Okinawa   Country:Japan  

  • ニュートリノ質量分光の実現に向けて

    津村浩二

    九州大学 素粒子理論セミナー  2019.11 

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    Event date: 2019.11

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:福岡   Country:Japan  

  • Geometry of Extended Higgs sector Invited International conference

    Koji Tsumura

    UCLA PACIFIC 2019  2019.9 

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    Event date: 2019.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Moorea   Country:Other  

  • ニュートリノ質量分光と背景事象抑制

    津村浩二

    素粒子物理学の進展 2019  2019.7 

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    Event date: 2019.7 - 2019.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • Scalar doublets charged under μ-τ-philic Zn flavor symmetry Invited International conference

    Koji Tsumura

    The 8th Workshop on Flavor Symmetries and Consequences in Accelerators and Cosmology (FLASY 2019)  2019.7 

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    Event date: 2019.7

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hefei   Country:China  

  • Syndetic Extension of Baryon and Lepton Numbers Invited International conference

    Koji Tsumura

    Exploration of Particle Physics and Cosmology with Neutrinos Workshop 2019  2019.7 

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    Event date: 2019.7

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Mie   Country:Japan  

  • 素粒子研究の発展と展望

    津村浩二

    岡山理科大学セミナー  2019.7 

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    Event date: 2019.7

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:岡山   Country:Japan  

  • 素粒子の理論 Invited

    津村浩二

    第9回高エネルギー物理春の学校  2019.5 

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    Event date: 2019.5

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:滋賀   Country:Japan  

  • Effect of Initial Spacial Phase in Neutrino Mass Spectroscopy Invited International conference

    Koji Tsumura

    The 5th Computational Chemistry Symposium -The main symposium of ICCMSE 2019-  2019.5 

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    Event date: 2019.5

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Rhodes   Country:Greece  

  • Recent Theoretical Development on RENP Invited International conference

    Koji Tsumura

    Okayama Mini-Workshop  2019.3 

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    Event date: 2019.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Okayama   Country:Japan  

  • Recent Theoretical Development on RENP International conference

    Koji Tsumura

    The 11th International Workshop on Fundamental Physics Using Atoms (FPUA2019)  2019.3 

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    Event date: 2019.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Okinawa   Country:Japan  

  • Poster Summary Invited International conference

    Koji Tsumura

    Higgs as a Probe of New Physics 2019  2019.2 

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    Event date: 2019.2

    Language:English  

    Venue:Osaka   Country:Japan  

  • Symmetry and Geometry in Generalized Higgs sector Invited International conference

    Koji Tsumura

    The OIST-NTU-Kyoto High Energy Physics Workshop  2018.11 

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    Event date: 2018.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Okinawa   Country:Japan  

  • Towards Neutrino Mass Spectroscopy

    Koji Tsumura

    基礎物理学研究所セミナー  2018.11 

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    Event date: 2018.11

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • 陽子崩壊探索のインパクト Invited

    津村浩二

    第二回琉球大学計算科学シンポジウム:“量子論の物理・化学的アプローチで迫る物質・自然界の謎”  2018.10 

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    Event date: 2018.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:沖縄   Country:Japan  

  • Recent Development on RENP Invited International conference

    Koji Tsumura

    Quantum Sensing for Dark Matter Searches and Neutrino Physics  2018.10 

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    Event date: 2018.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Padova   Country:Italy  

  • 対称性の破れと標準模型を超えた物理 Invited

    津村浩二

    46回 北陸信越地区 素粒子論グループ 合宿研究会  2018.9 

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    Event date: 2018.9

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:新潟   Country:Japan  

  • An SU(2)μτ model for Muon g-2 Anomaly International conference

    Koji Tsumura

    Workshop on Multi-Higgs models  2018.9 

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    Event date: 2018.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Lisbon   Country:Portugal  

  • B+Lを保存する陽子崩壊と長寿命暗黒物質

    津村浩二

    素粒子物理学の進展 2018  2018.8 

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    Event date: 2018.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • ニュートリノ質量分光の実現に向けて Invited

    津村浩二

    関西地域セミナー 2018  2018.6 

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    Event date: 2018.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • SU(2)μτ模型とミュオン異常磁気能率のずれ

    津村浩二

    日本物理学会第73回年次大会  2018.3 

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    Event date: 2018.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉   Country:Japan  

  • Scotogenic Seesaw Mechanism and Gauged Discrete Symmetries Invited International conference

    Koji Tsumura

    Unification and Development of the Neutrino Science Frontier  2018.3 

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    Event date: 2018.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • Neutrino Meets SIMP Dark Matter Invited International conference

    Koji Tsumura

    Workshop for Unification and Development of the Neutrino Science Frontier  2017.12 

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    Event date: 2017.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Shiga   Country:Japan  

  • Towards Neutrino Mass Spectroscopy (High-Energy Physics at Low Energy Frontier) Invited International conference

    Koji Tsumura

    East Asia Joint Workshop on Fields and Strings 2017, KEK Theory workshop 2017  2017.11 

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    Event date: 2017.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Maxion : Majoron as the QCD Axion in a Radiative Seesaw Model Invited International conference

    Koji Tsumura

    The 7th KIAS Workshop on Particle Physics and Cosmology and The 2nd KEK-NCTS-KIAS Workshop on Particle Physics Phenomenology  2017.11 

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    Event date: 2017.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Seoul   Country:Korea, Republic of  

  • Neutrinos Meet SIMP Invited International conference

    Koji Tsumura

    Energy Frontier in Particle Physics: LHC and Future Colliders  2017.9 

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    Event date: 2017.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • ニュートリノ質量分光における空間的振動位相印加のインパクト

    津村浩二

    日本物理学会 2017年 秋季大会  2017.9 

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    Event date: 2017.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:栃木   Country:Japan  

  • Towards Neutrino Mass Spectroscopy

    Koji Tsumura

    東大本郷 素粒子論セミナー  2017.7 

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    Event date: 2017.7

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:東京   Country:Japan  

  • 原子を使ったニュートリノ質量分光 Invited

    津村浩二

    第一回琉球大学計算科学シンポジウム:“素粒子と物性・化学は協力し合える!”  2017.6 

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    Event date: 2017.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:沖縄   Country:Japan  

  • Towards Neutrino Mass Spectroscopy International conference

    Koji Tsumura

    國家理論科學研究中心物理組(北部, 國立臺灣大學) HEPジャーナルクラブ  2017.6 

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    Event date: 2017.6

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Towards Neutrino Mass Spectroscopy Invited International conference

    Koji Tsumura

    The 3rd Computational Chemistry Symposium -The main symposium of ICCMSE 2017-  2017.4 

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    Event date: 2017.4

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Thessaloniki   Country:Greece  

  • ニュートリノ質量分光の実現に向けて

    津村浩二

    京都産業大学 益川塾セミナー(自然科学系)  2017.2 

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    Event date: 2017.2

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • ニュートリノ質量分光の実現に向けて

    津村浩二

    東京女子大学 素粒子セミナー  2016.12 

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    Event date: 2016.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:東京   Country:Japan  

  • Towards Neutrino Mass Spectroscopy Invited International conference

    Koji Tsumura

    The NTU-Kyoto Workshop  2016.11 

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    Event date: 2016.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Scotogenic Seesaw Mechanism & Discrete Gauge Symmetries International conference

    Koji Tsumura

    國家理論科學研究中心物理組(北部, 國立臺灣大學) HEPジャーナルクラブ  2016.11 

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    Event date: 2016.11

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Scotogenic Seesaw Mechanism & Discrete Gauge Symmetries International conference

    Koji Tsumura

    IBS-CTPU セミナー  2016.11 

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    Event date: 2016.11

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Daejeon   Country:Korea, Republic of  

  • 原子ニュートリノ観測のための誘電体導波路中のQED過程の解析 Invited

    津村浩二

    第5回 CUTE シンポジウム:量子状態計算「素粒子から化学へ」  2016.10 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:三重   Country:Japan  

  • 素粒子標準模型を超えて

    津村浩二

    京都大学 物理学第二教室セミナー  2016.10 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • 残存離散対称性を持つ輻射シーソー模型の分類

    津村浩二

    日本物理学会 2016年 秋季大会  2016.9 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:宮崎   Country:Japan  

  • LHCにおける二光子余剰事象はプランクスケールと無矛盾か?

    津村浩二

    静岡大学 素粒子論セミナー  2016.7 

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    Event date: 2016.7

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:静岡   Country:Japan  

  • Can the Models of LHC Diphoton Excesses be Valid up to the Planck scale? Invited International conference

    Koji Tsumura

    East Asia Joint Workshop on Fields and Strings  2016.5 

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    Event date: 2016.5 - 2016.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hefei   Country:China  

  • Can the New Physics Models be Valid up to the Planck scale? Invited International conference

    Koji Tsumura

    The NTU-Kyoto Workshop  2016.3 

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    Event date: 2016.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • VVレゾナンスの拡張ヒッグス模型による解釈 Invited

    津村浩二

    新学術領域研究会 テラスケール2015 先端加速器LHCが切り拓くテラスケールの素粒子物理学  2015.12 

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    Event date: 2015.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • Scalar Interpretations of the Diboson Excesses Invited International conference

    Koji Tsumura

    Diboson Theory Workshop (Diboson/Multilepton Subgroup Meeting)  2015.11 

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    Event date: 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Geneve   Country:Switzerland  

  • Landau Pole from Scalar N-plets Invited International conference

    Koji Tsumura

    KIAS-CFHEP Workshop and the 5th KIAS Workshop on Particle Physics and Cosmology  2015.11 

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    Event date: 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Seoul   Country:Korea, Republic of  

  • ヒッグスセクターはどこまで検証されたか? Invited

    津村浩二

    関西地域セミナー 2015  2015.7 

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    Event date: 2015.7

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • Unitarity and Electroweak Oblique Corrections Invited International conference

    Koji Tsumura

    CosKASI Dark Matter Workshop 2015  2015.6 

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    Event date: 2015.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Daejeon   Country:Korea, Republic of  

  • カストディアル対称性は必要か?

    津村浩二

    埼玉大学 素粒子論セミナー  2015.5 

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    Event date: 2015.5

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:埼玉   Country:Japan  

  • Unitarity and Electroweak Oblique Corrections Invited International conference

    Koji Tsumura

    The 2nd Joint Kyoto-NTU High Energy Theory Workshop  2015.3 

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    Event date: 2015.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Georgi-Machacek模型の付加的ヒッグスへの制限

    津村浩二

    日本物理学会第70回年次大会  2015.3 

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    Event date: 2015.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • Poster Summary II Invited International conference

    Koji Tsumura

    Higgs as a Probe of New Physics 2015  2015.2 

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    Event date: 2015.2

    Language:English  

    Venue:Toyama   Country:Japan  

  • A Model with the Higgs Septet International conference

    Koji Tsumura

    國立中央大學 セミナー  2014.12 

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    Event date: 2014.12

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Chungli   Country:Taiwan, Province of China  

  • Zero Higgs Doublet Model International conference

    Koji Tsumura

    中原大學 セミナー  2014.12 

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    Event date: 2014.12

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Chungli   Country:Taiwan, Province of China  

  • Fingerprinting Non-Minimal Higgs Sector Invited International conference

    Koji Tsumura

    Second KIAS-NCTS Joint Workshop  2014.12 

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    Event date: 2014.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • A Model with the Higgs Septet International conference

    Koji Tsumura

    國立成功大學 セミナー  2014.12 

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    Event date: 2014.12

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Tainan   Country:Taiwan, Province of China  

  • 素粒子標準模型 Invited

    津村浩二

    Flavor Physics Workshop 2014  2014.12 

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    Event date: 2014.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:静岡   Country:Japan  

  • Zero Higgs Doublet Mode Invited International conference

    Koji Tsumura

    International Workshop on "Theoretical Particle Physics 2014"  2014.11 

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    Event date: 2014.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hyogo   Country:Japan  

  • What if K_W \neq K_Z ? -- Zero Higgs Doublet Model -- International conference

    Koji Tsumura

    The 2014 International Workshop on Future Linear Colliders (LCWS14)  2014.10 

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    Event date: 2014.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Belgrade   Country:Other  

  • Radiative Seesaw Models with Leptoquarks Invited International conference

    Koji Tsumura

    Run 2 kick-off meeting for leptoquarks, lepton+jets black hole searches in ATLAS  2014.10 

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    Event date: 2014.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Geneve   Country:Switzerland  

  • From the Higgs Coupling to New Physics Beyond the SM Invited International conference

    Koji Tsumura

    Progress in String Theory and Particle Phenomenology -the Kick-off Workshop of SPIRITS-  2014.9 

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    Event date: 2014.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • Zero Higgs doublet model

    津村浩二

    E研 夏の学校 2014  2014.8 

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    Event date: 2014.8 - 2014.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:福井   Country:Japan  

  • Zero Higgs Doublet Model International conference

    Koji Tsumura

    Summer Institute 2014  2014.8 

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    Event date: 2014.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Yamanashi   Country:Japan  

  • A Model with the Higgs Septet

    Koji Tsumura

    東北大学 素粒子論セミナー  2014.7 

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    Event date: 2014.7

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:宮城   Country:Japan  

  • Tau Lepton in Higgs Physics

    Koji Tsumura

    北海道大学 素粒子セミナー  2014.7 

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    Event date: 2014.7

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:北海道   Country:Japan  

  • A Model with the Higgs Septet

    Koji Tsumura

    北海道大学 素粒子セミナー  2014.7 

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    Event date: 2014.7

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:北海道   Country:Japan  

  • タウを使ったヒッグス模型の決定

    津村浩二

    大阪市立大学 数理・素粒子セミナー  2014.6 

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    Event date: 2014.6

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:大阪   Country:Japan  

  • PQ対称性の破れと冷たい暗黒物質の安定性

    津村浩二

    日本物理学会第69回年次大会  2014.3 

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    Event date: 2014.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神奈川   Country:Japan  

  • BrやWW->hhからのhiggsの模型の制限 Invited

    津村浩二

    新学術領域研究 先端加速器LHCが切り拓くテラスケールの素粒子物理学 〜真空と時空への新たな挑戦〜 研究会  2014.3 

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    Event date: 2014.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • ヒッグス模型とタウの物理

    津村浩二

    京都大学 素粒子論セミナー  2013.12 

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    Event date: 2013.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • What if the Higgs coupling deviates from the SM one International conference

    Koji Tsumura

    International Workshop on Future Linear Colliders 2013 (LCWS2013)  2013.11 

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    Event date: 2013.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Tokyo   Country:Japan  

  • A model with the Higgs septet Invited International conference

    Koji Tsumura

    International Workshop on "Theoretical Particle Physics 2013"  2013.11 

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    Event date: 2013.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • The Higgs boson mixes with an SU(2) septet International conference

    Koji Tsumura

    KEK Theory Meeting 2013 on Particle Physics Phenomenology (fall)  2013.9 

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    Event date: 2013.9 - 2013.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • 7表現ヒッグス場

    津村浩二

    日本物理学会 2013年 秋季大会  2013.9 

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    Event date: 2013.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:高知   Country:Japan  

  • 二重荷電ヒッグスのタウへの崩壊を利用した模型の区別

    津村浩二

    埼玉大学 素粒子論セミナー  2013.9 

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    Event date: 2013.9

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:埼玉   Country:Japan  

  • The Higgs boson mixes with an SU(2) septet International conference

    Koji Tsumura

    The 21st International Conference on Supersymmetry and Unification of Fundamental Interactions (SUSY2013)  2013.8 

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    Event date: 2013.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Trieste   Country:Italy  

  • ヒッグスセクターの解明に向けて

    津村浩二

    京都大学 物理学第二教室セミナー  2013.8 

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    Event date: 2013.8

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • 7表現ヒッグス場

    津村浩二

    素粒子物理学の進展 2013  2013.8 

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    Event date: 2013.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • 拡張ヒッグスの物理 Invited

    津村浩二

    加速器・物理合同 ILC 夏の合宿2013  2013.7 

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    Event date: 2013.7

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:富山   Country:Japan  

  • Lepton number violation at the LHC with leptoquarks and diquarks International conference

    Koji Tsumura

    The 3rd Workshop on Flavor Symmetries (FLASY13)  2013.7 

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    Event date: 2013.7

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Niigata   Country:Japan  

  • 7表現ヒッグス場

    津村浩二

    広島大学 素研セミナー  2013.6 

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    Event date: 2013.6

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:広島   Country:Japan  

  • The Higgs boson mixes with an SU(2) septet International conference

    Koji Tsumura

    European Linear Collider Workshop (ECFA LC2013)  2013.5 

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    Event date: 2013.5

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hamburg   Country:Germany  

  • Heavy Higgs Invited

    津村浩二

    新学術領域研究 先端加速器LHCが切り拓くテラスケールの素粒子物理学 〜真空と時空への新たな挑戦〜 研究会  2013.5 

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    Event date: 2013.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:愛知   Country:Japan  

  • 線形加速器におけるtanβの測定

    津村浩二

    日本物理学会第68回年次大会  2013.3 

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    Event date: 2013.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:広島   Country:Japan  

  • The Higgs boson mixes with an SU(2) septet Invited International conference

    Koji Tsumura

    QFPU Final International Forum  2013.3 

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    Event date: 2013.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Gifu   Country:Japan  

  • Discrimination of models including doubly charged scalar bosons using tau decays International conference

    Koji Tsumura

    KEK Theory Meeting 2013 on Particle Physics Phenomenology  2013.3 

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    Event date: 2013.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Two Higgs Doublet Models Invited International conference

    Koji Tsumura

    Higgs as a Probe of New Physics 2013  2013.2 

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    Event date: 2013.2

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Toyama   Country:Japan  

  • QCD Corrections to Electric Dipole Moment from Dimension-six Four-Quark Operators International conference

    Koji Tsumura

    Strong Coupling Gauge Theory 2012  2012.12 

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    Event date: 2012.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Aichi   Country:Japan  

  • Discrimination of models including H ±± by using tau decay

    Koji Tsumura

    23rd Hadron Collider Physics Symposium 2012, HCP 2012  2013.9 

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    Event date: 2012.11

    Language:English  

    Venue:Kyoto   Country:Japan  

    The doubly charged scalar boson (H±±) is introduced in several models of the new physics beyond the standard model. The H±± can have Yukawa interactions with two left-handed charged leptons or two righthanded charged leptons. We study kinematical properties of H±± decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of the tau decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the H ±± decay products [1].

  • Discrimination of models including doubly charged scalar bosons using tau decays International conference

    Koji Tsumura

    Hadron Collider Physics Symposium 2012  2012.11 

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    Event date: 2012.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • コライダー実験で探るニュートリノ模型 Invited

    津村浩二

    ILC 加速器・物理合同勉強会  2012.11 

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    Event date: 2012.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:茨城   Country:Japan  

  • 拡張ヒッグス模型とタウの物理@LHC

    津村浩二

    茨城大学 素研セミナー  2012.11 

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    Event date: 2012.11

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:茨城   Country:Japan  

  • Search for extended Higgs sector at the LHC by using tau lepton decays

    津村浩二

    東京大学(駒場素粒子論)セミナー  2012.10 

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    Event date: 2012.10

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:東京   Country:Japan  

  • Extra Higgs bosons and tanβ Invited International conference

    Koji Tsumura

    International Workshop on Future Linear Colliders 2012 (LCWS2012)  2012.10 

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    Event date: 2012.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Texas  

  • Discrimination of models with doubly charged scalar bosons at the LHC Invited International conference

    Koji Tsumura

    International Workshop on "Theoretical Particle Physics 2012"  2012.9 

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    Event date: 2012.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Nara   Country:Japan  

  • Discrimination of models including doubly charged scalar bosons using tau decays International conference

    Koji Tsumura

    The 12th International Workshop on Tau Lepton Physics  2012.9 

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    Event date: 2012.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Aichi   Country:Japan  

  • タウ崩壊による二重荷電ヒッグスの湯川相互作用の分類

    津村浩二

    日本物理学会 2012年 秋季大会  2012.9 

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    Event date: 2012.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • Models for neutrino masses at the LHC

    津村浩二

    E研 夏の学校 2012  2012.9 

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    Event date: 2012.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:福井   Country:Japan  

  • RG improvement of the Higgs mediated EDM International conference

    Koji Tsumura

    Workshop on Multi-Higgs models  2012.8 

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    Event date: 2012.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Lisbon   Country:Portugal  

  • Discrimination of models with doubly charged scalar bosons International conference

    Koji Tsumura

    Summer Institute 2012  2012.8 

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    Event date: 2012.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Nantou   Country:Taiwan, Province of China  

  • RG improvement of the CEDM via CP violating 4-Fermi operators

    Koji Tsumura

    高エネルギー加速器研究機構 理論セミナー  2012.7 

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    Event date: 2012.7

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:茨城   Country:Japan  

  • 4体フェルミ演算子の中性子EDMへ与えるQCD補正

    津村浩二

    素粒子物理学の進展 2012  2012.7 

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    Event date: 2012.7

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • Leptophilic two Higgs doublet model at the LHC

    Koji Tsumura

    基礎物理学研究所セミナー  2012.6 

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    Event date: 2012.6

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:京都   Country:Japan  

  • Multi tau lepton signatures in leptophilic two Higgs doublet model at the ILC International conference

    Koji Tsumura

    Joint ACFA Physics / Detector Workshop and GDE meeting on Linear Collider (KILC12)  2012.4 

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    Event date: 2012.4

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Daegu   Country:Korea, Republic of  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model

    Koji Tsumura

    名古屋大学 EHQGセミナー  2012.4 

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    Event date: 2012.4

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:愛知   Country:Japan  

  • LHCにおけるスカラー対生成からの多重タウレプトン信号

    津村浩二

    日本物理学会第67回年次大会  2012.3 

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    Event date: 2012.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:兵庫   Country:Japan  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model International conference

    Koji Tsumura

    LHC Focus Group Workshop on Collider and Dark Matter Physics  2012.3 

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    Event date: 2012.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model International conference

    Koji Tsumura

    國家理論科學研究中心物理組 HEPジャーナルクラブ  2012.3 

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    Event date: 2012.3

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Hsinchu   Country:Taiwan, Province of China  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model International conference

    Koji Tsumura

    KEK Theory Meeting 2012 on Particle Physics Phenomenology  2012.2 

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    Event date: 2012.2 - 2012.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model Invited International conference

    Koji Tsumura

    Toyama mini workshop on particle physics and cosmology  2012.2 

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    Event date: 2012.2

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Toyama   Country:Japan  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model International conference

    Koji Tsumura

    Physics opportunities with LHC at 7 TeV  2012.2 

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    Event date: 2012.2

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Multi-tau-lepton signatures at the LHC in the two Higgs doublet model International conference

    Koji Tsumura

    國家理論科學研究中心物理組(北部, 國立臺灣大學) HEPジャーナルクラブ  2012.2 

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    Event date: 2012.2

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Heavy electrically charge neutral fermions (Is it Majorana or Dirac particle?) Invited International conference

    Koji Tsumura

    Focus workshop on Heavy Quarks at LHC  2012.1 

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    Event date: 2012.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Heavy Long-lived quarks Invited International conference

    Koji Tsumura

    Focus workshop on Heavy Quarks at LHC  2012.1 

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    Event date: 2012.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Indirect bounds on heavy scalar masses of the two-Higgs-doublet model International conference

    Koji Tsumura

    2012 Annual Meeting of the Physical Society of ROC  2012.1 

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    Event date: 2012.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Chiayi   Country:Taiwan, Province of China  

  • Lepton flavor violation with fourth generations Invited International conference

    Koji Tsumura

    Third Workshop on Beyond 3 Generation Standard Model --- Under the light of the initial LHC results  2011.10 

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    Event date: 2011.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Istanbul   Country:Turkey  

  • Indirect bounds on heavy scalar masses of the two-Higgs-doublet model in light of recent Higgs boson searches International conference

    Koji Tsumura

    國立清華大學 理論セミナー  2011.10 

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    Event date: 2011.10

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Hsinchu   Country:Taiwan, Province of China  

  • Multi-tau lepton signatures in leptophilic two higgs doublet model at the ILC

    Shinya Kanemura, Koji Tsumura, Hiroshi Yokoya

    International Workshop on Future Linear Colliders, LCWS 2011  2011.12 

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    Event date: 2011.9

    Language:English  

    Venue:Granada   Country:Spain  

    We study the feasibility of the Type-X two Higgs doublet model (THDM-X) at collider experiments. In the THDM-X, new Higgs bosons mostly decay into tau leptons in the wide range of the parameter space. Such scalar bosons are less constrained by current experimental data, because of the suppressed quark Yukawa interactions. We discuss a search strategy of the THDM-X with multi-tau lepton final states at International linear collider and Large Hadron Collider. By using the collinear approximation, we show that a four tau lepton signature (e+e- → HA → 4τ ) can be a clean signal.

  • Multi tau lepton signatures in leptophilic two Higgs doublet model at the ILC International conference

    Koji Tsumura

    International Workshop on Future Linear Colliders 2011 (LCWS2011)  2011.9 

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    Event date: 2011.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Granada   Country:Spain  

  • Leptophilic Higgs boson in the two-Higgs-doublet model International conference

    Koji Tsumura

    國立交通大學 理論セミナー  2011.5 

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    Event date: 2011.5

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Hsinchu   Country:Taiwan, Province of China  

  • Leptophilic Higgs boson in the two-Higgs-doublet model International conference

    Koji Tsumura

    國立師範大學 理論セミナー  2011.4 

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    Event date: 2011.4

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Phenomenology in the Higgs Triplet Model with the A_4 Symmetry International conference

    Koji Tsumura

    國家理論科學研究中心物理組 HEPジャーナルクラブ  2011.3 

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    Event date: 2011.3

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Hsinchu   Country:Taiwan, Province of China  

  • Higgs boson pair production in new physics models at hadron, lepton, and photon colliders

    津村浩二

    富山大学 理論物理学セミナー  2011.2 

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    Event date: 2011.2

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:富山   Country:Japan  

  • Phenomenology in the Higgs Triplet Model with the A_4 Symmetry

    Koji Tsumura

    大阪大学 素粒子論セミナー  2011.2 

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    Event date: 2011.2

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:大阪   Country:Japan  

  • Phenomenology in the Zee Model with the A_4 Symmetry International conference

    Koji Tsumura

    2011 Annual Meeting of the Physical Society of ROC in Taipei  2011.1 

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    Event date: 2011.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Phenomenology in the Higgs Triplet Model with the A_4 Symmetry International conference

    Koji Tsumura

    中央研究院物理研究所セミナー  2010.12 

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    Event date: 2010.12

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • Higgs boson pair production in new physics models at hadron, lepton, and photon colliders Invited International conference

    Koji Tsumura

    LC10, New physics: complemetarities between direct and indirect searches  2010.11 

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    Event date: 2010.11 - 2010.12

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Rome   Country:Italy  

  • Phenomenology in the Higgs Triplet Model with the A_4 Symmetry International conference

    Koji Tsumura

    國家理論科學研究中心物理組(北部, 國立臺灣大學) HEPジャーナルクラブ  2010.11 

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    Event date: 2010.11

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Taipei   Country:Taiwan, Province of China  

  • レプトンと強く結合するヒッグスボソン

    津村浩二

    日本大学大学院特別講義  2010.10 

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    Event date: 2010.10

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:東京   Country:Japan  

  • Higgs Triplet Model with A4 symmetry International conference

    Koji Tsumura

    国際理論物理学センター HEPセミナー  2010.9 

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    Event date: 2010.9

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Trieste   Country:Italy  

  • Models of Yukawa interaction in the two Higgs doublet model International conference

    Koji Tsumura

    DESY THEORY WORKSHOP 2009 Collider Phenomenology  2009.9 

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    Event date: 2009.9 - 2009.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hamburg   Country:Germany  

  • Lepton Flavour Violation at an Electron-Photon Collider Invited International conference

    Koji Tsumura

    LC09, e+e- Physics at the TeV Scale and the Dark Matter connection  2009.9 

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    Event date: 2009.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Perugia   Country:Italy  

  • Leptophilic Higgs bosons in the two-Higgs-doublet model International conference

    Koji Tsumura

    国際理論物理学センター HEPセミナー  2009.3 

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    Event date: 2009.3

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Trieste   Country:Italy  

  • Higgs boson pair production at the Photon Linear Collider in the two Higgs doublet model

    Daisuke Harada, Eri Asakawa, Shinya Kanemura, Yasuhiro Okada, Koji Tsumura

    8th General Meeting of the ILC Physics Working Group  2009.12 

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    Event date: 2009.1

    Language:English  

    Venue:Tsukuba   Country:Japan  

    We calculate the cross section of the lightest Higgs boson pair production at the Photon Linear Collider in the two Higgs doublet model. We focus on the scenario in which the lightest Higgs boson has the standard model like couplings to gauge bosons. We take into account the one-loop correction to the hhh coupling as well as additional one-loop diagrams due to charged bosons to the γγ → hh helicity amplitudes. We discuss the impact of these corrections on the hhh coupling measurement at the Photon Linear Collider.

  • Measuring Higgs boson associated Lepton Flavour Violation in electron-photon collisions at the ILC

    Shinya Kanemura, Koji Tsumura

    8th General Meeting of the ILC Physics Working Group  2009.12 

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    Event date: 2009.1

    Language:English  

    Venue:Tsukuba   Country:Japan  

    We study the LFV Higgs production processes e-γ → l- φ (l = μ, τ; φ = H, A) as a probe of Higgs mediated LFV couplings at an electron-photon collider, where H and A are extra CP even and odd Higgs bosons, respectively, in the two Higgs doublet model. Under the constraints from the current data of muon and tau rare decay, the cross section can be significantly large. It would improve the experimental upper bounds on the effective LFV coupling constants. In addition, the chirality nature of the LFV Higgs coupling constants can be measured by selecting electron beam polarizations.

  • Flavonの現象論

    津村浩二

    富山大学 理論物理学セミナー  2009.1 

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    Event date: 2009.1

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:富山   Country:Japan  

  • Flavonの現象論

    津村浩二

    大阪大学 素粒子論セミナー  2008.12 

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    Event date: 2008.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:大阪   Country:Japan  

  • Flavon phenomenology at the LHC

    津村浩二

    立命館大学 素粒子論セミナー  2008.12 

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    Event date: 2008.12

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:滋賀   Country:Japan  

  • Higgs boson pair production at the photon linear collider in the two Higgs doublet model

    Eri Asakawa, Daisuke Harada, Shinya Kanemura, Yasuhiro Okada, Koji Tsumura

    2008 Linear Collider Workshop, LCWS 2008 and International Linear Collider Meeting, ILC 2008  2008.12 

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    Event date: 2008.11

    Language:English  

    Venue:Chicago, IL   Country:United States  

    We calculate the cross section of the lightest Higgs boson pair production at the Photon Linear Collider in the two Higgs doublet model. We focus on the scenario in which the lightest Higgs boson has the standard model like couplings to gauge bosons. We take into account the one-loop correction to the hhh coupling as well as additional one-loop diagrams due to charged bosons to the γγ → hh helicity amplitudes. We discuss the impact of these corrections on the hhh coupling measurement at the Photon Linear Collider.

  • Impact of higher dimensional operators on Higgs boson phenomenology International conference

    Koji Tsumura

    International Linear Collider ECFA Workshop 2008  2008.6 

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    Event date: 2008.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Warsaw   Country:Poland  

  • 将来加速器における非標準ヒッグス結合の測定

    津村浩二

    富山大学 理論物理学セミナー  2008.3 

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    Event date: 2008.3

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:富山   Country:Japan  

  • Impact of dim-6 Higgs-fermion and Higgs genuine operators on processes at the future colliders International conference

    Koji Tsumura

    Joint ACFA Physics and Detector Workshop and GDE meeting on International Linear Collider (TILC08)  2008.3 

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    Event date: 2008.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Miyagi   Country:Japan  

  • Lepton flavour violation in the Higgs boson decay International conference

    Koji Tsumura

    国際理論物理学センター HEPセミナー  2007.12 

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    Event date: 2007.12

    Language:English   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:Trieste   Country:Italy  

  • 将来加速器におけるトップ湯川結合の測定と新物理の効果

    津村浩二

    名古屋大学 E研セミナー  2007.7 

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    Event date: 2007.7

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:愛知   Country:Japan  

  • New physics effect on the top-Yukawa coupling at ILC

    Shinya Kanemura, Koichi Matsuda, Daisuke Nomura, Koji Tsumura

    2007 International Linear Collider Workshop, LCWS 2007 and International Linear Collider Meeting, ILC 2007  2007.12 

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    Event date: 2007.5 - 2007.6

    Language:English  

    Venue:Hamburg   Country:Germany  

    Measurement of the top-Yukawa coupling is important to understand the fermion mass generation mechanism and dynamics of electroweak symmetry breaking. We discuss the top quark anomalous couplings which can be described by higher dimensional operators. We investigate the process e-e+ → W-W+vv̄ → tt̄vv̄ to study the contribution of the anomalous top-Higgs coupling to the cross section. The effect of the dimension-six top-Higgs interaction on the cross section can be a few hundred percent greater than the SM prediction. Such a large effect can be measured at the International Linear Collider.

  • New Physics effect on the Top-Yukawa coupling International conference

    Koji Tsumura

    Linear Collider Workshop 2007 (LCWS2007 and ILC2007)  2007.5 

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    Event date: 2007.5 - 2007.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hamburg   Country:Germany  

  • 超対称模型における将来加速器でのスカラー対生成と超対称パラメータの決定

    津村浩二

    日本物理学会 2007年 春季大会  2007.3 

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    Event date: 2007.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • New Physics search via W-W+→ tt at the ILC International conference

    Koji Tsumura

    KEK Theory Meeting 2007 on Particle Physics Phenomenology  2007.3 

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    Event date: 2007.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Dimension-six top-Higgs interaction and its effect in collider phenomenology International conference

    Koji Tsumura

    ILC-ECFA and GDE Joint Meeting  2006.11 

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    Event date: 2006.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Valencia   Country:Spain  

  • Dimension-six top-higgs interaction and its effect in collider phenomenology

    Koji Tsumura, S. Kanemura, D. Nomura

    Annual Meeting of the Division of Particles and Fields of the American Physical Society, DPF 2006, and the Annual Fall Meeting of the Japan Particle Physics Community  2006.1 

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    Event date: 2006.10 - 2006.11

    Language:English  

    Venue:Honolulu, HI   Country:United States  

  • Dimension-six top-Higgs interaction and its effect in collider phenomenology International conference

    Koji Tsumura

    Joint Meeting of Pacific Region Particle Physics Communities (DPF2006+JPS2006…)  2006.10 

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    Event date: 2006.10 - 2006.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hawai  

  • トップ湯川結合に対する新しい物理の効果と将来加速器での検証

    津村浩二

    素粒子物理学の進展 2006  2006.7 

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    Event date: 2006.7 - 2006.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:京都   Country:Japan  

  • ILCにおけるトップ湯川結合に対する高次演算子の効果

    津村浩二

    東北大学 素粒子論セミナー  2006.6 

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    Event date: 2006.6

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:宮城   Country:Japan  

  • 将来加速器におけるトップ湯川結合に対する高次演算子の効果

    津村浩二

    富山大学 理論物理学セミナー  2006.4 

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    Event date: 2006.4

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:富山   Country:Japan  

  • トップ湯川結合に対する高次演算子の効果とILCでの検証

    津村浩二

    日本物理学会第61回年次大会  2006.3 

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    Event date: 2006.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:愛媛   Country:Japan  

  • Genuine dimension-six top-Higgs interaction and its effect on collider phenomenology International conference

    Koji Tsumura

    KEK Theory Meeting 2006 on Particle Physics Phenomenology  2006.3 

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    Event date: 2006.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • ヒッグス粒子崩壊で探るレプトンフレーバーの破れ

    津村浩二

    金沢大学 素粒子論セミナー  2005.10 

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    Event date: 2005.10

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:石川   Country:Japan  

  • Lepton flavor violation in the Higgs boson decays International conference

    Koji Tsumura

    Hanoi-Forum 2005  2005.9 

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    Event date: 2005.9

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hanoi   Country:Viet Nam  

  • Frogatt-Nielsen機構から導かれるCPの破れ

    津村浩二

    日本物理学会 2005年 秋季大会  2005.9 

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    Event date: 2005.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪   Country:Japan  

  • Lepton flavor violation in Higgs boson decays International conference

    Koji Tsumura

    Summer Institute 2005  2005.8 

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    Event date: 2005.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Yamanashi   Country:Japan  

  • ヒッグス粒子崩壊で探すレプトンフレーバーの破れ

    津村浩二

    三者若手夏の学校 2005  2005.8 

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    Event date: 2005.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:東京   Country:Japan  

  • Lepton Flavor Violating Decays of Higgs bosons under the Rare Tau Decay Results International conference

    Koji Tsumura

    The 8th ACFA Workshop on Physics and Detector at the Linear Collider  2005.7 

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    Event date: 2005.7

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Daegu   Country:Korea, Republic of  

  • Lepton flavor violation in Higgs boson decays under the rare tau decay results International conference

    Koji Tsumura

    Progress in Particle Physics 2005  2005.6 

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    Event date: 2005.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kyoto   Country:Japan  

  • ヒッグス粒子崩壊に於けるレプトンフレーバーの破れ

    津村浩二

    関西地域セミナー 2005  2005.6 

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    Event date: 2005.6

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:兵庫   Country:Japan  

  • 湯川相互作用によるレプトンフレーバーの破れ

    津村浩二

    日本物理学会第60回年次大会  2005.3 

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    Event date: 2005.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:千葉   Country:Japan  

  • Measurement of lepton flavor violating yukawa couplings at ILC

    S. Kanemura, T. Ota, K. Tsumura

    2005 International Linear Collider Workshop, LCWS 2005  2005.12 

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    Event date: 2005.3

    Language:English  

    Venue:Stanford, CA   Country:United States  

    We discuss lepton flavor violation (LFV) associated with tau leptons in the general framework of the two Higgs doublet model, in which LFV couplings are introduced as a deviation from Model II Yukawa interaction. Parameters of the model are constrained from experimental results and also from requirements of theoretical consistencies such as vacuum stability and perturbative unitarity. Current data for LFV rare tau decays provide substantial upper limits on the LFV Yukawa couplings in the large tanβ region, which are comparable with predictions in fundamental theories. Here tan β is the ratio of vacuum expectation values of the two Higgs doublets. A search for the LFV decays φ0→ τ±μ±e) of neutral Higgs bosons (φ0 = h, H and A) at future collider experiments can be useful to further constrain the LFV couplings, especially in the relatively small tanβ region (tan β ≲ 30), where rare tau decay data cannot give any strong limit.

  • Lepton flavor violation in the Higgs boson decay International conference

    Koji Tsumura

    KEK Theory Meeting 2005 on Particle Physics Phenomenology  2005.3 

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    Event date: 2005.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Lepton Flavor Violation in the Higgs boson decay International conference

    Koji Tsumura

    Sapporo Winter School in Niseko '05  2005.1 

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    Event date: 2005.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hokkaido   Country:Japan  

  • CPの破れとFrogatt-Nielsen機構

    津村浩二

    日本物理学会 2004年 秋季大会  2004.9 

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    Event date: 2004.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:高知   Country:Japan  

  • ニュートリノ湯川行列とレプトンフレーバーの破れ

    津村浩二

    三者若手夏の学校 2004  2004.8 

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    Event date: 2004.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:長野   Country:Japan  

  • Yukawa Matrix and Lepton Flavor Violation International conference

    Koji Tsumura

    The 6th International Workshop on Neutrino Factories and Superbeams (NuFACT04)  2004.7 

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    Event date: 2004.7 - 2004.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Osaka   Country:Japan  

  • Phase contribution for LFV International conference

    Koji Tsumura

    The 21st International Conference on Neutrino Physics and Astrophysics (NEUTRINO2004)  2004.6 

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    Event date: 2004.6

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Paris   Country:France  

  • レプトンフレーバーの破れに於ける位相の寄与

    津村浩二

    埼玉大学 素粒子論セミナー  2004.6 

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    Event date: 2004.6

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    Venue:埼玉   Country:Japan  

  • CPの破れとFN機構

    津村浩二

    関西地域セミナー 2004  2004.5 

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    Event date: 2004.5

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:大阪   Country:Japan  

  • LFVとCP位相

    津村浩二

    日本物理学会第59回年次大会  2004.3 

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    Event date: 2004.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:福岡   Country:Japan  

  • The Dependence of LFV on phases International conference

    Koji Tsumura

    KEK Theory Meeting 2004 on Particle Physics Phenomenology  2004.3 

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    Event date: 2004.3

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Ibaraki   Country:Japan  

  • Lepton Flavor Violating process and CP-phases International conference

    Koji Tsumura

    Sapporo Winter School in Niseko '04  2004.1 

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    Event date: 2004.1

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Hokkaido   Country:Japan  

  • RG effect from GUT Scale for neutrino mixing

    津村浩二

    日本物理学会 2003年 秋季大会  2003.9 

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    Event date: 2003.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:宮崎   Country:Japan  

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MISC

Professional Memberships

  • The Physical Society of Japan

  • Japan Particle and Nuclear Theory Forum

Committee Memberships

  • 京都大学 基礎物理学研究所 共同利用委員会 議長団   代表   Domestic

    2023.4 - 2025.3   

  • 素粒子論グループ 素粒子論委員会   委員長   Domestic

    2022.4 - 2023.3   

  • 京都大学 基礎物理学研究所 共同利用委員会   Steering committee member   Domestic

    2021.4 - 2023.3   

  • 素粒子論グループ 事務局   連絡責任者   Domestic

    2020.10 - 2021.9   

  • 日本物理学会九州支部   Organizer   Domestic

    2020.4 - 2021.3   

  • 素粒子論グループ 素粒子論委員会   Organizer   Domestic

    2020.4 - 2021.3   

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Academic Activities

  • オンライン物理講話担当メンバー

    日本物理学会  ( Japan ) 2024.4 - 2026.3

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    Type:Competition, symposium, etc. 

  • 領域運営委員(素粒子論)

    日本物理学会  ( Japan ) 2024.4 - 2025.3

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    Type:Competition, symposium, etc. 

  • 開催組織委員 International contribution

    Higgs as a Probe of New Physics 2023  ( Japan ) 2023.6

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    Type:Competition, symposium, etc. 

  • 開催組織委員

    Kagoshima Workshop on Particles, Fields and Strings 2023  ( Japan ) 2023.2

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    Type:Competition, symposium, etc. 

  • 開催組織委員 International contribution

    Summer Institute 2022  ( Japan ) 2022.9

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    Type:Competition, symposium, etc. 

  • 理論セッション世話人

    2021年9月 ILC夏の合宿2021 (オンライン):世話人  ( Japan ) 2021.9

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    Type:Competition, symposium, etc. 

    Number of participants:156

  • 開催組織委員 International contribution

    Higgs as a Probe of New Physics 2021  ( Japan ) 2021.3

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    Type:Competition, symposium, etc. 

  • 世話人

    素粒子物理学の進展 2020  ( Japan ) 2020.8 - 2020.9

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    Type:Competition, symposium, etc. 

  • Organizing Committee International contribution

    New Physics at Low Scale 2020  ( Machinaka-Campus, Miyazaki University Japan ) 2020.3

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    Type:Competition, symposium, etc. 

  • Physics Letters B International contribution

    2013.6 - 2013.11

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    Type:Academic society, research group, etc. 

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Research Projects

  • 拡張有効理論で迫るヒッグスセクターの新原理

    Grant number:22K03620  2022 - 2025

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

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    Authorship:Principal investigator  Grant type:Scientific research funding

  • ニュートリノで拓く素粒子と宇宙

    Grant number:18H05535  2018 - 2022

    Japan Society for the Promotion of Science・Ministry of Education, Culture, Sports, Science and Technology  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

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    Authorship:Coinvestigator(s)  Grant type:Scientific research funding

  • 標準理論を超えた新現象とニュートリノで探る新しい素粒子像

    Grant number:18H05543  2018 - 2022

    Japan Society for the Promotion of Science・Ministry of Education, Culture, Sports, Science and Technology  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

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    Authorship:Principal investigator  Grant type:Scientific research funding

Class subject

  • 特殊相対性理論・電気力学B

    2024.12 - 2025.2   Winter quarter

  • 特殊相対性理論・電気力学(R2以前入学者用)

    2024.10 - 2025.3   Second semester

  • 解析力学

    2024.10 - 2025.3   Second semester

  • 特殊相対性理論・電気力学A

    2024.10 - 2024.12   Fall quarter

  • 身の回りの物理学B

    2024.4 - 2024.6   Spring quarter

  • 特殊相対性理論・電気力学B

    2023.12 - 2024.2   Winter quarter

  • 解析力学

    2023.10 - 2024.3   Second semester

  • 特殊相対性理論・電気力学(R2以前入学者用)

    2023.10 - 2024.3   Second semester

  • 特殊相対性理論・電気力学A

    2023.10 - 2023.12   Fall quarter

  • 物理学特別講義11

    2023.4 - 2023.9   First semester

  • 身の回りの物理学B

    2023.4 - 2023.6   Spring quarter

  • 特殊相対性理論・電気力学

    2022.10 - 2023.3   Second semester

  • 解析力学

    2022.10 - 2023.3   Second semester

  • 物理学特別講義1

    2022.4 - 2022.9   First semester

  • 物理学総合演習

    2022.4 - 2022.9   First semester

  • 特殊相対性理論・電気力学

    2021.10 - 2022.3   Second semester

  • 物理学特別講義28

    2021.10 - 2022.3   Second semester

  • 解析力学

    2021.10 - 2022.3   Second semester

  • 物理学総合演習

    2021.4 - 2021.9   First semester

  • 特殊相対性理論・電気力学

    2020.10 - 2021.3   Second semester

  • 物理学総合演習

    2020.4 - 2020.9   First semester

  • 身の回りの物理学B

    2019.12 - 2020.2   Winter quarter

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FD Participation

  • 2023.3   Role:Participation   Title:【物理学科FD】物理数学の教育と効果的な演習に向けて

    Organizer:Undergraduate school department

  • 2022.3   Role:Participation   Title:【物理学科FD】ティーチング・フェロー制度の概要と講義での活用に向けて

    Organizer:Undergraduate school department

  • 2021.4   Role:Participation   Title:令和3年度 第1回全学FD(新任教員の研修)

    Organizer:University-wide

  • 2021.3   Role:Participation   Title:【物理学FD】ハイブリッド講義の実践例と講義活性化

    Organizer:[Undergraduate school/graduate school/graduate faculty]

Visiting, concurrent, or part-time lecturers at other universities, institutions, etc.

  • 2021  東京大学素粒子物理国際研究センター  Classification:Affiliate faculty  Domestic/International Classification:Japan 

  • 2020  東京大学素粒子物理国際研究センター  Classification:Affiliate faculty  Domestic/International Classification:Japan 

Other educational activity and Special note

  • 2024  Class Teacher  学部

  • 2024  Class Teacher  学部

  • 2023  Class Teacher  学部

  • 2023  Class Teacher  学部

  • 2022  Class Teacher  学部

  • 2022  Class Teacher  学部

  • 2021  Class Teacher  学部

  • 2021  Class Teacher  学部

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Outline of Social Contribution and International Cooperation activities

  • 九州大学オープンキャンパス2023 特別講義 講義2「量子論入門」
    令和4年度 九州大学理学部先端自然科学講演会・福岡県高等学校理科部会 夏季研修会 物理学講演2「素粒子で迫る宇宙」
    高等専門学校3・4年生の方々を対象とした「九州大学理学部物理学科公開講座オンライン」バーチャルラボツアー・座談会2021

Acceptance of Foreign Researchers, etc.

  • 広島大学

    Acceptance period: 2023.1   (Period):Less than 2 weeks

    Nationality:Japan

  • KIAS

    Acceptance period: 2022.11   (Period):Less than 2 weeks

    Nationality:Taiwan, Province of China

Travel Abroad

  • 2022.12

    Staying countory name 1:Taiwan, Province of China   Staying institution name 1:National Taiwan University