J-GLOBAL         Last updated: Nov 4, 2019 at 22:55
Kyushu University
Job title
Assistant Professor
Ph. D(Osaka University), Master of Science(Osaka University), Bachelor of Science(Hiroshima University)

Research Areas


Academic & Professional Experience

Dec 2013
Oct 2019
Assistant Professor, Kyoto University 
Apr 2012
Nov 2013
Research Associate, Nagoya University Graduate School of Science, Division of Particle and Astrophysical Science
Oct 2010
Mar 2012
Postdoctoral Fellow, National Taiwan University
Oct 2007
Oct 2010
Postdoctoral Fellow, International Center for Theoretical Physics
Apr 2007
Sep 2007
Postdoctoral Fellow, KEK

Published Papers

Model with a gauged lepton flavor SU(2) symmetry
Cheng-Wei Chiang, Koji Tsumura
JHEP 1805 (2018) 069      May 2018   [Refereed]
Minoru Tanaka, Koji Tsumura, Noboru Sasao, Satoshi Uetake, Motohiko Yoshimura
Phys. Rev. D 96, 113005 (2017)      Oct 2017   [Refereed]
We study radiative neutrino pair emission in deexcitation process of atoms
taking into account 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 im...
Ernest Ma, Takahiro Ohata, Koji Tsumura
Phys. Rev. D 96, 075039 (2017)      Aug 2017   [Refereed]
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...
Shu-Yu Ho, Takashi Toma, Koji Tsumura
JHEP 1707 (2017) 101      May 2017   [Refereed]
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...
Yuta Hamada, Koji Tsumura, Daiki Yasuhara
Phys. Rev. D 95, 103505      May 2017   [Refereed]
Koji Tsumura, Masatoshi Yamada, Yuya Yamaguchi
JCAP07(2017)044      Apr 2017   [Refereed]
In this work, we investigate the spectra of gravitational waves produced by
chiral symmetry breaking in dark quantum chromodynamics (dQCD) sector. The dark
pion (Tex) can be a dark matter candidate as weakly interacting massive
particle (WIMP) o...
Minoru Tanaka, Koji Tsumura, Noboru Sasao, Motohiko Yoshimura
Prog Theor Exp Phys (2017) 2017 (4): 043B03.      Apr 2017   [Refereed]
Shu-Yu Ho, Takashi Toma, Koji Tsumura
Phys. Rev. D 94, 033007      Aug 2016   [Refereed]
Yuta Hamada, Hikaru Kawai, Kiyoharu Kawana,Koji Tsumura
Phys. Rev. D 94, 014007      Jul 2016   [Refereed]
Yuji Omura, Kazuhiro Tobe, Koji Tsumura
Phys. Rev. D 92, 055015      Sep 2015   [Refereed]
Yuta Hamada, Kiyoharu Kawana, Koji Tsumura
Phys.Lett. B747 (2015) 238-244      May 2015   [Refereed]
We consider the Standard Model with a new scalar field Tex which is a
Tex representation of the Tex with a hypercharge Tex. The
renormalization group running effects on the new scalar quartic coupling
constants are evaluated. Even if ...
Cheng-Wei Chiang, Koji Tsumura
JHEP 1504 (2015) 113      Jan 2015   [Refereed]
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 alpha between the
two custodial singlet...
Ryo Nagai, Masaharu Tanabashi, Koji Tsumura
Phys. Rev. D 91, 034030 (2015)      Sep 2014   [Refereed]
Introducing 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 ...
Shinya Kanemura, Koji Tsumura, Kei Yagyu, Hiroshi Yokoya
Phys. Rev. D90, 075001 (2014)      Jun 2014   [Refereed]
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 ...
Basudeb Dasgupta, Ernest Ma, Koji Tsumura
Phys. Rev. D 89, 041702 (2014)      Aug 2013   [Refereed]
The Peccei-Quinn anomalous global U(1)_{PQ} symmetry is important not only
for solving the strong CP problem with a cosmologically relevant axion, but it
may also be the origin of a residual Z_2 symmetry. This new symmetry may be
responsible for a...
Kaori Fuyuto, Junji Hisano, Natsumi Nagata, Koji Tsumura
JHEP 1312 (2013) 010      Aug 2013   [Refereed]
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...
Shinya Kanemura, Koji Tsumura, Hiroshi Yokoya
Phys. Rev. D88, 055010 (2013)      May 2013   [Refereed]
In the two Higgs doublet model, Tex is an important parameter, which
is defined as the ratio of the vacuum expectation values of the doublets. We
study how accurately Tex can be determined at linear colliders via the
precision meas...
Junji Hisano, Koji Tsumura
Phys. Rev. D87, 053004 (2013)      Jan 2013   [Refereed]
We study a 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 se...
Masaya Kohda, Hiroaki Sugiyama, Koji Tsumura
Phys. Lett. B718, 1436 (2013)      Oct 2012   [Refereed]
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 lept...
Hiroaki Sugiyama, Koji Tsumura, Hiroshi Yokoya
Phys. Lett. B717 (2012) 229      Jul 2012   [Refereed]
The doubly charged scalar boson (H^{\pm\pm}) is introduced in several models
of the new physics beyond the standard model. The H^{\pm\pm} has Yukawa
interactions with two left-handed charged leptons or two right-handed charged
leptons depending on...

Conference Activities & Talks

Scotogenic Seesaw Mechanism and Gauged Discrete Symmetries [Invited]
Unification and Development of the Neutrino Science Frontier   Mar 2018   
Neutrino Meets SIMP Dark Matter [Invited]
Workshop for Unification and Development of the Neutrino Science Frontier   Dec 2017   
Towards Neutrino Mass Spectroscopy (High-Energy Physics at Low Energy Frontier)
East Asia Joint Workshop on Fields and Strings 2017, KEK Theory workshop 2017   Nov 2017   
Maxion : Majoron as the QCD Axion in a Radiative Seesaw Model [Invited]
The 7th KIAS Workshop on Particle Physics and Cosmology and The 2nd KEK-NCTS-KIAS Workshop on Particle Physics Phenomenology   Nov 2017   
Neutrinos Meet SIMP [Invited]
Energy Frontier in Particle Physics: LHC and Future Colliders   Sep 2017   
Lepton Flavor Violation in the Lepton Sector [Invited]
The 15th Conference on Flavor Physics and CP Violation   Jun 2017   
Towards Neutrino Mass Spectroscopy [Invited]
The 3rd Computational Chemistry Symposium -The main symposium of ICCMSE 2017-   Apr 2017   
Towards Neutrino Mass Spectroscopy [Invited]
The NTU-Kyoto Workshop   Nov 2016   
Can the Models of LHC Diphoton Excesses be Valid up to the Planck scale? [Invited]
East Asia Joint Workshop on Fields and Strings   May 2016   
Can the New Physics Models be Valid up to the Planck scale? [Invited]
The NTU-Kyoto Workshop   Mar 2016   
Scalar Interpretations of the Diboson Excesses [Invited]
Diboson Theory Workshop (Diboson/Multilepton Subgroup Meeting)   Nov 2015   
Landau Pole from Scalar N-plets [Invited]
KIAS-CFHEP Workshop and the 5th KIAS Workshop on Particle Physics and Cosmology   Nov 2015   
Prospects of LHC Run II [Invited]
Developments in String Theory and Quantum Field Theory   Nov 2015   
Unitarity and Electroweak Oblique Corrections [Invited]
CosKASI Dark Matter Workshop 2015   Jul 2015   
Unitarity and Electroweak Oblique Corrections [Invited]
The 2nd Joint Kyoto-NTU High Energy Theory Workshop   Mar 2015   
Poster Summary II [Invited]
Higgs as a Probe of New Physics 2015   Feb 2015   
Fingerprinting Non-Minimal Higgs Sector [Invited]
Second KIAS-NCTS Joint Workshop   Dec 2014   
Zero Higgs Doublet Model [Invited]
International Workshop on "Theoretical Particle Physics 2014"   Nov 2014   
What if K_W \neq K_Z ? -- Zero Higgs Doublet Model --
The 2014 International Workshop on Future Linear Colliders (LCWS14)   Oct 2014   
Radiative Seesaw Models with Leptoquarks [Invited]
Run 2 kick-off meeting for leptoquarks, lepton+jets black hole searches in ATLAS   Oct 2014   

Association Memberships