Updated on 2026/06/16

Information

 

写真a

 
FUJIWARA MOTOKO
 
Organization
Faculty of Science Department of Physics Associate Professor
School of Interdisciplinary Science and Innovation Department of Interdisciplinary Science and Innovation（Concurrent）
Title
Associate Professor
External link

Research Areas

  • Natural Science / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

Degree

  • Ph.D. （ 2022.3 Nagoya University ）

Research History

  •  Faculty of Science Department of Physics  Associate Professor 

    2026.4 - Present

  • University of Toyama Faculty of Science Assistant Professor 

    2022.12 - 2026.3

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    Country：Japan

  • Technical University of Munich Faculty of Science, Department of Physics postdoc researcher 

    2022.10 - 2024.11

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    Country：Germany

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  • The University of Tokyo Graduate School of Science postdoc researcher 

    2022.4 - 2022.9

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    Country：Japan

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  • Nagoya University 物理学科 Academic Researcher DC2 research fellow

    2020.4 - 2022.3

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    Country：Japan

Education

  • Nagoya University   Faculty of Science   Department of Physics

    2019.4 - 2022.3

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    Country：Japan

  • Nagoya University   Faculty of Science   Department of Physics

    2017.4 - 2019.3

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    Country：Japan

  • Keio University   Faculty of Science   Department of Physics

    2013.4 - 2017.3

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    Country：Japan

Research Interests・Research Keywords

  • Research theme： Neutrino

    Keyword： Neutrino

    Research period： 2026

  • Research theme： Particle phenomenology

    Keyword： Particle phenomenology

    Research period： 2026

  • Research theme： Particle Cosmology

    Keyword： Particle Cosmology

    Research period： 2026

  • Research theme： Dark matter

    Keyword： Dark matter

    Research period： 2026

  • Research theme： Phenomenological Study of Particle Dark Matter

    Keyword： Dark Matter

    Research period： 2017.11 - Present

Awards

  • JPS Young Scientist Awards 2025

    2025.10   Physical Society of Japan   Theoretical study on dark matter search using neutron star temperature observation

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  • Early career support for women at NAT

    2024.5   Talent Management and Diversity Council  

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  • Springer Thesis

    2023.5   Springer   Electroweak-Interacting Spin-1 Dark Matter and Its Phenomenology

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  • Nagoya University President's Award

    2022.3   Nagoya University   KMI Science Communication Team

    KMI Science, Communication Team

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Papers

▼display all

Books

  • Electroweak-Interacting Spin-1 Dark Matter and Its Phenomenology

    （Role：Sole author）

    Springer Singapore  2023.5    （ ISBN:9789819910342 ）

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  • Mit Erfolg zum Humboldt-Forschungsstipendium

    （Role：Joint author）

    素粒子論研究・電子版  2022.9 

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Presentations

  • The WIMP Paradigm and Beyond: Status and Future Directions Invited

    Motoko Fujiwara

    TeV Particle Astrophysics 2026  2026.9 

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    Event date： 2026.8 - 2026.9

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Effective Field Theory Across Scales Invited

    Motoko Fujiwara

    30th International Summer Institute on Phenomenology of Elementary Particle Physics and Cosmology (SI2026)  2026.8 

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    Event date： 2026.8

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Compact Star as Dark Matter Probe Invited

    Motoko Fujiwara

    Dark Matter as a portal to New Physics 2026  2026.1 

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    Event date： 2026.1

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Effective Theory Construction and precision in dark matter gamma-ray spectrum: spin-0, 1/2, and 1 Invited

    Motoko Fujiwara

    JPS symposium  2025.9 

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    Event date： 2025.9

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • What's next for two-year research stay in Germany? Invited

    Motoko Fujiwara

    JSPS Career Forum 2025  2025.5 

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    Event date： 2025.5

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Neutron star as dark matter probe Invited

    Motoko Fujiwara

    Lecture of the Young Scientist Award of JPS  2025.3 

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    Event date： 2025.3

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Soft Collinear Effective Theory for heavy dark matter annihilation ~spin-0, 1/2 and spin-1~ Invited

    Motoko Fujiwara

    KEK-PH 2025  2025.2 

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    Event date： 2025.2

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Particle Dark Matter ~Current status of theory & search~ Invited

    Motoko Fujiwara

    2023年度 第53回 天文・天体物理若手夏の学校  2023.8 

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    Event date： 2023.8

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

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  • Progress in Particle Physics and Cosmology –Academic Journey from Hiyoshi– Invited

    Motoko Fujiwara

    慶應義塾大学 理工学概論  2026.1 

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    Event date： 2026.1

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

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  • Cosmic-ray ~Connection between Particle and Universe~

    Motoko Fujiwara

    富山県高文連自然科学専門部 生徒研修会  2025.12 

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    Event date： 2025.12

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • From Peaks to Particles: Cosmic-ray Outreach @Mt. Tateyama

    Motoko Fujiwara

    OSECHI Autumn Camp 2025  2025.11 

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    Event date： 2025.11

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Boosted dark matter from semi-annihilations in the galactic center

    Motoko Fujiwara

    JPS 80th Annual Meeting  2025.9 

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    Event date： 2025.9

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Recent Progress in Particle Dark Matter Invited

    Motoko Fujiwara

    Progress in Particle Physics  2025.9 

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    Event date： 2025.9

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Particle Dark Matter: A Bird’s-Eye View of Recent Progress Invited

    Motoko Fujiwara

    第 52 回 北陸信越地区 素粒子論グループ研究会  2025.7 

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    Event date： 2025.7

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Resummed multi-line gamma-ray spectra for Cherenkov Telescopes from heavy spin-1 dark matter

    Motoko Fujiwara

    Higgs as a Probe of New Physics 2025  2025.6 

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    Event date： 2025.6

    Language：English   Presentation type：Oral presentation (general)  

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  • Soft Collinear Effective Theory for heavy dark matter annihilation: spin-0, 1/2, and 1

    Motoko Fujiwara

    Special Seminar at MITP  2025.5 

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    Event date： 2025.5

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

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  • Resummed gamma-ray spectrum from electroweakly interacting spin-1 dark matter

    Motoko Fujiwara

    New Higgs Working Group, 40th regular meeting  2025.1 

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    Event date： 2025.1

    Language：English   Presentation type：Oral presentation (general)  

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  • Tidal disruption events as dark matter probe

    Motoko Fujiwara

    Invisibles24  2024.7 

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    Event date： 2024.7

    Language：English   Presentation type：Poster presentation  

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  • Dark Matter Heating vs Vortex Creep Heating in Old Neutron Star

    Motoko Fujiwara

    Quarkonium meet Dark Matter  2024.3 

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    Event date： 2024

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Dark matter self-interaction: the fate of the spike & annihilation-boosted dark matter in the Milky Way galaxy

    Motoko Fujiwara

    MITP workshop "Dark Matter Landscape: From Feeble to Strong Interactions"  2024 

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    Event date： 2024

    Language：English   Presentation type：Oral presentation (general)  

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  • Neutron stars as new laboratories Invited

    Motoko Fujiwara

    SFB1258 Colloquium  2023.12 

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    Event date： 2023.12

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Dark Matter Heating vs Vortex Creep Heating in Old Neutron Star

    Motoko Fujiwara

    RCNP workshop -Microscopic approach from pair correlation to pair condensation-  2023.9 

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    Event date： 2023.9

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Dark Matter Heating vs Vortex Creep Heating in Old Neutron Star

    Motoko Fujiwara

    The Dark Side of the Universe (DSU2023)  2023.7 

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    Event date： 2023.7

    Language：English   Presentation type：Oral presentation (general)  

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  • Dark Matter Heating vs Vortex Creep Heating in Old Neutron Star

    Motoko Fujiwara

    Dark Matter 2023  2023.5 

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    Event date： 2023.5

    Language：English   Presentation type：Oral presentation (general)  

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  • Current status of WIMP Dark Matter: Theory and Search Invited

    Motoko Fujiwara

    Kashiwa Dark Matter Symposium 2022  2022.11 

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    Event date： 2022.11 - 2022.12

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Dark Matter Capture in Neutron Stars

    Motoko Fujiwara

    Virtual Humboldt Colloquium "Top Global Research” and the Humboldt Network: New Frontiers of German-Japanese Scientific Cooperation  2022.11 

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    Event date： 2022.11

    Language：English   Presentation type：Oral presentation (general)  

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  • Electroweak Vector Dark Matter Invited

    Motoko Fujiwara

    The 2nd DMnet International Symposium "Direct and Indirect Dark Matter Search"  2022.9 

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    Event date： 2022.9

    Language：Japanese   Presentation type：Oral presentation (invited, special)  

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  • Capture of Electroweak Multiplet Dark Matter in Neutron Stars

    Motoko Fujiwara

    The Progress of the Particle Physics 2018 (PPP2018)  2022.8 

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    Event date： 2022.8 - 2022.9

    Language：Japanese   Presentation type：Poster presentation  

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  • Capture of Electroweak Multiplet Dark Matter in Neutron Stars

    Motoko Fujiwara

    IBS and KMI Joint Workshop 2022  2022.8 

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    Event date： 2022.8

    Language：English   Presentation type：Oral presentation (general)  

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  • Capture of Electroweak Multiplet Dark Matter in Neutron Stars

    Motoko Fujiwara

    RCNP workshop on Neutron Star 2022  2022.8 

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    Event date： 2022.8

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Capture of Dark Matter in Neutron Star Invited

    Motoko Fujiwara

    Unraveling the History of the Universe and Matter Evolution with Underground Physics UGAP2022, 13th-15th, Jun., 2022 Tokyo University of Science  2022.6 

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    Event date： 2022.6

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Electroweakly interacting spin-1 dark matter and its phenomenology

    Motoko Fujiwara

    Physics in LHC and Beyond  2022.5 

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    Event date： 2022.5

    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Electroweakly interacting spin-1 dark matter and its phenomenology

    Motoko Fujiwara

    KEK-PH + KEK-COSMO joint mini-workshop  2022.3 

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    Event date： 2022.3

    Language：English   Presentation type：Oral presentation (invited, special)  

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  • Electroweakly interacting spin-1 dark matter and its phenomenology

    Motoko Fujiwara

    New Higgs Working Group, 32nd regular meeting  2022.2 

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    Event date： 2022.2

    Language：Japanese   Presentation type：Oral presentation (general)  

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MISC

  • Neutrino Diffusion within Dark Matter Spikes

    Motoko Fujiwara, Gonzalo Herrera, Shunsaku Horiuchi

    2024.12

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    Multi-messenger observations of astrophysical transients provide powerful probes of the underlying physics of the source as well as beyond the Standard Model effects. We explore transients that can occur in the vicinity of supermassive black holes at the center of galaxies, including tidal disruption events (TDEs), certain types of blazars, or even supernovae. In such environments, the dark matter (DM) density can be extremely high, resembling a dense spike or core. We study a novel effect of neutrino diffusion sustained via frequent scatterings off DM particles in these regions. We show that for transients occurring within DM spikes or cores, the DM-neutrino scattering can delay the arrival of neutrinos with respect to photons, but this also comes with a suppression of the neutrino flux and energy loss. We apply these effects to the specific example of TDEs, and demonstrate that currently unconstrained parameter space of DM-neutrino interactions can account for the sizable $O$(days) delay of the tentative high-energy neutrinos observed from some TDEs.

    arXiv

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    Other Link： https://arxiv.org/pdf/2412.00805v1

  • New description of the scaling evolution of the cosmological magneto-hydrodynamic system

    Fumio Uchida, Motoko Fujiwara, Kohei Kamada, Jun'ichi Yokoyama

    2022.12

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    We present a new description of cosmological evolution of the primordial magnetic field under the condition that it is non-helical and its energy density is larger than the kinetic energy density. We argue that the evolution can be described by four different regimes, according to whether the decay dynamics is linear or not, and whether the dominant dissipation term is the shear viscosity or the drag force. Using this classification and conservation of the Hosking integral, we present analytic models to adequately interpret the results of various numerical simulations of field evolution with variety of initial conditions. It is found that, contrary to the conventional wisdom, the decay of the field is generally slow, exhibiting the inverse transfer, because of the conservation of the Hosking integral. Using the description proposed here, we may trace the intermediate evolution history of the magnetic field and clarify whether each process governing its evolution is frozen or not, which is essential to follow the evolution of relatively weak magnetic fields.

    DOI： 10.1016/j.physletb.2023.138002

    arXiv

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    Other Link： https://arxiv.org/pdf/2212.14355v1

Professional Memberships

  • The Physical Society of Japan

    2018.5 - Present

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Research Projects

  • Refining Gamma-Ray Predictions for Extra-Dimensional Dark Matter: Discrimination from Supersymmetric Models

    Grant number：25K23378  2025.7 - 2027.3

    Grants-in-Aid for Scientific Research  Grant-in-Aid for Research Activity Start-up

    藤原 素子

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    Grant type：Scientific research funding

    超対称性理論と余剰次元理論は、素粒子標準模型を超える物理の最有力候補として、各々特有の機構で電弱相互作用する暗黒物質を予言する。両者のシグナルを観測的に識別できれば、背後に存在する物質の相互作用原理を見通す重大な示唆を得る。超対称性理論の予言はすでに高精度で導出されている一方、余剰次元理論は理論構造が複雑で暗黒物質の現象解析が十分に確立していない。本研究では、「暗黒物質の対消滅に由来するダブルピークを持ったガンマ線スペクトル」に注目し、TeV ガンマ線望遠鏡において、ピーク構造が検出可能か検証する。また、確立した予言をもとに、超対称性理論との識別可能性を定量的に導出することを目指す。

    CiNii Research

  • 地域特性を活かしたアウトリーチ活動の立ち上げ 〜空から降る素粒子を使って地球を測ろう〜

    2025.7 - 2026.3

    富山大学 令和7年度学裁量経費「富山大学教育研究活動活性化支援」  科学コミュニケーション

    藤原素子

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    Grant type：On-campus funds, funds, etc.

  • 次世代暗黒物質直接探索実験とWIMP暗黒物質の理論的研究

    Grant number：20J12392  2020.4 - 2022.3

    日本学術振興会   科学研究費助成事業 特別研究員奨励費 

    Motoko Fujiwara

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    Authorship：Principal investigator  Grant type：Scientific research funding

Class subject

  • 共創のための数学

    2026.12 - 2027.2   Winter quarter

  • 〔自然〕数学Ａ

    2026.12 - 2027.2   Fall quarter

Outline of Social Contribution and International Cooperation activities

  • As an social activity, I give public lectures and organize workshops using cosmic-ray search instruments.

Social Activities

  • Career development as young researcher in germany

    Role(s)：Contribution

    JSPS Bonn Office  NEWSLETTER ぼんぼん時計  2026.3

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Acceptance of Foreign Researchers, etc.

  • 富山大学

    Acceptance period： 2025.10   （Period）：Less than 2 weeks

    Nationality：Norway

    Business entity：Japan Society for the Promotion of Science

Travel Abroad

  • 2022.10 - 2024.11

    Staying countory name 1：Germany   Staying institution name 1：ミュンヘン工科大学