Higaki, Tetsutaro

写真a

Affiliation

Faculty of Science and Technology, Department of Physics (Yagami)

Position

Assistant Professor/Senior Assistant Professor

Career 【 Display / hide

  • 2013.04
    -
    2015.03

    KEK: 大学共同利用機関法人 高エネルギー加速器研究機構

  • 2012.01
    -
    2013.03

    理化学研究所

  • 2010.04
    -
    2012.01

    DESY(Deutsches Elektronen-Synchrotron)

  • 2006.04
    -
    2010.03

    東北大学

Academic Background 【 Display / hide

  • 2001.04
    -
    2006.03

    Kyoto University

    Graduate School, Completed

Academic Degrees 【 Display / hide

  • 博士(理学), Kyoto University, Coursework, 2006.03

 

Research Areas 【 Display / hide

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

Research Keywords 【 Display / hide

  • 素粒子論:素粒子現象論・宇宙論、超弦理論現象論・宇宙論

 

Books 【 Display / hide

Papers 【 Display / hide

  • 4D effective action from non-Abelian DBI action with magnetic flux background

    Yoshihiko Abe, Tetsutaro Higaki, Tatsuo Kobayashi, Shintaro Takada, Rei Takahashi

    Physical Review D (American Physical Society)  104 ( 12 ) 126020-1 - 126020-15 2021.12

    Research paper (other academic), Joint Work, Accepted,  ISSN  24700010

     View Summary

    We study a systematic derivation of four-dimensional N=1 supersymmetric effective theory from a ten-dimensional non-Abelian Dirac-Born-Infeld action compactified on a six-dimensional torus with magnetic fluxes on the D-branes. We find a new type of matter Kähler metric, while gauge kinetic function and superpotential are consistent with previous studies. For the ten-dimensional action, we use a symmetrized trace prescription and focus on the bosonic part up to O(F4). In the presence of the supersymmetry, four-dimensional chiral fermions can be obtained via index theorem. The new matter Kähler metric is independent of flavor but depends on the fluxes, 4D dilaton, Kähler moduli, and complex structure moduli and will be always positive definite if an induced Ramond-Ramond charge of the D-branes on which matters are living are positive. We read the superpotential from an F-term scalar quartic interaction derived from the ten-dimensional action and the contribution of the new matter Kähler metric to the scalar potential which we derive turns out to be consistent with the supergravity formulation.

  • Implications of the weak gravity conjecture in anomalous quiver gauge theories

    Yoshihiko Abe, Tetsutaro Higaki, Rei Takahashi

    Physical Review D (American Physical Society)  102 ( 065004 )  2020.09

    Research paper (scientific journal), Joint Work, Accepted,  ISSN  24700010

     View Summary

    © 2020 authors. Published by the American Physical Society. We argue a smallness of gauge couplings in Abelian quiver gauge theories, taking the anomaly cancellation condition into account. In theories of our interest there exist chiral fermions leading to chiral gauge anomalies, and an anomaly-free gauge coupling tends to be small, and hence can give a nontrivial condition of the weak gravity conjecture. As concrete examples, we consider U(1)k gauge theories with a discrete symmetry associated with cyclic permutations between the gauge groups, and identify anomaly-free U(1) gauge symmetries and the corresponding gauge couplings. Owing to this discrete symmetry, we can systematically study the models and we find that the models would be examples of the weak coupling conjecture. It is conjectured that a certain class of chiral gauge theories with too many U(1) symmetries may be in the swampland. We also numerically study constraints on the couplings from the scalar weak gravity conjecture in a concrete model. These constraints may have a phenomenological implication to model building of a chiral hidden sector as well as the visible sector.

  • Note on a solution to domain wall problem with the Lazarides-Shafi mechanism in axion dark matter models

    Chatterjee C., Higaki T., Nitta M.

    Physical Review D (Physical Review D)  101 ( 7 )  2020.04

    ISSN  24700010

     View Summary

    © 2020 authors. Published by the American Physical Society. Axion is a promising candidate of dark matter. After the Peccei-Quinn symmetry breaking, axion strings are formed and attached by domain walls when the temperature of the universe becomes comparable to the QCD scale. Such objects can cause cosmological disasters if they are long lived. As a solution for it, the Lazarides-Shafi mechanism is often discussed through introduction of a new non-Abelian (gauge) symmetry. We study this mechanism in detail and show configuration of strings and walls. Even if Abelian axion strings with a domain wall number greater than 1 are formed in the early universe, each of them is split into multiple Alice axion strings due to a repulsive force between the Alice strings even without domain wall. When domain walls are formed as the universe cools down, a single Alice string can be attached by a single wall because a vacuum is connected by a non-Abelian rotation without changing energy. Even if an Abelian axion string attached by domain walls is created due to the Kibble Zurek mechanism at the chiral phase transition, such strings are also similarly split into multiple Alice strings attached by walls in the presence of the domain wall tension. Such walls do not form stable networks since they collapse by the tension of the walls, emitting axions.

  • A low-scale flavon model with a ℤ_N symmetry

    Higaki T., Kawamura J.

    Journal of High Energy Physics (Journal of High Energy Physics)  2020 ( 3 )  2020.03

    ISSN  11266708

     View Summary

    © 2020, The Author(s). We propose a model that explains the fermion mass hierarchy by the Froggatt-Nielsen mechanism with a discrete ℤNF symmetry. As a concrete model, we study a super-symmetric model with a single flavon coupled to the minimal supersymmetric Standard Model. Flavon develops a TeV scale vacuum expectation value for realizing flavor hierarchy, an appropriate μ-term and the electroweak scale, hence the model has a low cutoff scale. We demonstrate how the flavon is successfully stabilized together with the Higgs bosons in the model. The discrete flavor symmetry ℤNF controls not only the Standard Model fermion masses, but also the Higgs potential and a mass of the Higgsino which is a good candidate for dark matter. The hierarchy in the Higgs-flavon sector is determined in order to make the model anomaly-free and realize a stable electroweak vacuum. We show that this model can explain the fermion mass hierarchy, realistic Higgs-flavon potential and thermally produced dark matter at the same time. We discuss flavor violating processes induced by the light flavon which would be detected in future experiments.

  • Flavor structure, Higgs boson mass and dark matter in supersymmetric model with vector-like generations

    Tetsutaro Higaki, Michinobu Nishida, Naoyuki Takeda

    Progress of Theoretical and Experimental Physics 2017 ( 8 ) 1 - 36 2017.08

    Research paper (scientific journal), Joint Work, Accepted

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Presentations 【 Display / hide

  • New 4D EFT from 10D non-Abelian DBI action in magnetic compactifications

    Tetsutaro Higaki

    KEK Theory Workshop 2021, 

    2021.12

    Oral presentation (general)

  • 4D effective action from 10D non-Abelian DBI action with magnetic flux background

    Tetsutaro Higaki

    Strings and Fields 2021, 

    2021.08

    Oral presentation (general)

  • Implications of the weak gravity conjecture in anomalous quiver gauge theories

    Tetsutaro Higaki

    KEK Theory workshop 2020 (online) , 

    2020.12

    Oral presentation (general), KEK theory group

  • A low-scale flavon model with a Z_N flavor symmetry

    檜垣 徹太郎

    基研研究会 素粒子物理学の進展2020, 

    2020.08

    Poster presentation

  • Note on a solution to domain wall problem with the Lazarides-Shafi mechanism in axion dark matter models

    Tetsutaro Higaki

    14th International Conference on Gravitation, Astrophysics and Cosmology (Online (Taipei, Taiwan)) , 

    2020.08

    Oral presentation (general)

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Research Projects of Competitive Funds, etc. 【 Display / hide

  • 沼地予想とモジュライから探る究極理論の観測的性質(基盤研究(C))

    2022.04
    -
    2027.03

    基盤研究(C), Principal investigator

  • 隠れたセクターの場や粒子が引き起こす多様な宇宙現象を用いた究極理論探査(基盤研究A・分担)

    2015.04
    -
    2018.03

    Coinvestigator(s)

  • 超弦理論におけるモジュライ場の現象論的、宇宙論的側面の研究(若手研究B)

    2013.04
    -
    2015.03

    Principal investigator

  • 超弦理論におけるモジュライ場の現象論的、宇宙論的側面の研究(日本学術振興会 優秀若手研究者海外派遣事業 (特別研究員))

    2009
    -
    2010

    Principal investigator

  • 超弦理論におけるモジュライ場の現象論的、宇宙論的側面の研究(学振PD)

    2007.04
    -
    2010.03

    Principal investigator

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Awards 【 Display / hide

  • 慶應義塾国際化(SG)奨励賞

    2016

  • 第8回素粒子メダル奨励賞受賞

    2013

Other 【 Display / hide

  • 2021年09月

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    「基研研究会 素粒子物理学の進展2021」組織委員

  • 基研研究会 素粒子物理学の進展2020

    2020年08月

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    「基研研究会 素粒子物理学の進展2020」組織委員

  • 2019年07月

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    「基研研究会 素粒子物理学の進展2019」組織委員

  • 超弦理論と素粒子論現象論

    2018年08月

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    集中講義:原子核三者若手 夏の学校2018

  • 2018年08月

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    「基研研究会 素粒子物理学の進展2018」組織委員

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Courses Taught 【 Display / hide

  • PHYSICS SEMINAR 3

    2022

  • PHYSICS D

    2022

  • PHYSICS C

    2022

  • LITERATURE OF PHYSICS

    2022

  • INDEPENDENT STUDY ON FUNDAMENTAL SCIENCE AND TECHNOLOGY

    2022

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Courses Previously Taught 【 Display / hide

  • 物理学演習第2

    Keio University

    2017.04
    -
    2018.03

    Autumn Semester, Seminar

  • 場の理論(隔年開講)

    Keio University

    2017.04
    -
    2018.03

    Spring Semester, Lecture

  • 物理学A・B

    Keio University

    2017.04
    -
    2018.03

    Spring Semester, Seminar

 

Social Activities 【 Display / hide

  • 科学入門講座:宇宙は何からできているだろうか

    (慶應義塾湘南藤沢高等部)

    2016.03

Memberships in Academic Societies 【 Display / hide

  • 物理学会

     
  • 素粒子論グループ

     

Committee Experiences 【 Display / hide

  • 2016.04
    -
    2018.03

    素粒子論委員