The 3rd Winter Toyama Mini-Workshop on Particle Physics and Cosmology "Basis of the Universe with Revolutionary Ideas 2018 (BURI2018)"

Tamokuteki-Hall (B243), A238 (Faculty of Science, University of Toyama)

Tamokuteki-Hall (B243), A238

Faculty of Science, University of Toyama

3190 Gofuku, Toyama 930-8555, Japan

Welcome to Toyama Mini-Workshop BURI2018

The 3rd Winter Toyama Mini-Workshop on Particle Physics and Cosmology "Basis of the Universe with Revolutionary Ideas 2018 (BURI2018)" will be held on January 16-17, 2018 on Gofuku Campus of the University of Toyama.

The aim of this mini-workshop is to discuss unresolved issues in particle physics and particle cosmology. Topics covered include:

  • Collider Phenomenology
  • Flavor Physics
  • Model Building
  • Particle Cosmology

The workshop will take place from 9:00 a.m. on Tuesday, January 16 till 16:00 on Wednesday, January 17 (plan). 

Important Dates

  • Deadline for Registration / Abstract Submission: January 5, 2018
  • Banquet: January 16, 2018

A list of invited speakers includes

  • Chuan-Ren Chen (National Taiwan Normal University)
  • Motoi Endo (KEK)
  • Koji Ishiwata (Kanazawa University)
  • Pyungwon Ko (KIAS)
  • Kentarou Mawatari (Osaka University)
  • and more

Organizing Committee

  • Junji Hisano (Nagoya University)
  • Mitsuru Kakizaki (University of Toyama) (Chair)
  • Shinya Kanemura (Osaka University)
  • Takeo Moroi (University of Tokyo)


  • Mitsuru Kakizaki (University of Toyama) 
  • Phone: 076-445-6593 / email: kakizaki

Past Workshops


Registration for BURI2018
  • Chuan-Ren Chen
  • Hiroaki Sugiyama
  • Katsuya Hashino
  • Keita Nakanishi
  • Kentarou Mawatari
  • kenzo ISHIKAWA
  • Kin-ya Oda
  • Kodai Sakurai
  • Koji Ishiwata
  • Masahito Ogata
  • Mayumi Aoki
  • Minoru Tanaka
  • Mitsunori Kubota
  • Mitsuru Kakizaki
  • Motoi Endo
  • Norimi Yokozaki
  • Pyungwon Ko
  • Shin Suzuki
  • Shinya Kanemura
  • Shohei Okawa
  • Shu-Yu Ho
  • So Chigusa
  • Tomohiro Abe
  • Toshinori Matsui
  • Yoshihiro Shigekami
  • Yuji Omura
  • Yutaro Shoji
  • Tuesday, 16 January
    • 09:30 09:55
      Registration 25m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

    • 10:00 10:15
      Announcement 15m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      I will give a brief introduction.

      Speaker: Mitsuru Kakizaki (University of Toyama)
    • 10:15 11:00
      Dark pion DM : WIMP vs. SIMP 45m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Dark pion could be a good candidate of dark matter. It could be either SIMP or SIMP, depending on the parameters of the model. I will discuss these two possibilities in my talk.

      Speaker: Pyungwon Ko
    • 11:00 11:30
      Realization of a spontaneous gauge and supersymmetry breaking vacuum 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      It is one of the major issues to realize a vacuum which breaks supersymmetry (SUSY) and R-symmetry, in a supersymmetric model. We study the model, where the same sector breaks the gauge symmetry and SUSY. In general, the SUSY breaking model without gauge symmetry has a flat direction at the minimum of F-term scalar potential. When we introduce U(1) gauge symmetry to such a SUSY breaking model, there can appear a runaway direction. Such a runway direction can be lifted by loop effects, and the gauge symmetry breaking and SUSY breaking are realized. The R-symmetry, that is assigned to break SUSY, is also spontaneously broken at the vacuum. This scenario can be extended to non-Abelian gauge theories. We also discuss application to the Pati-Salam model and the SU(5) grand unified theory. We see that non-vanishing gaugino masses are radiatively generated by the R-symmetry breaking and the gauge messenger contribution.

      Speaker: Dr Yuji Omura
    • 11:30 12:00
      Enhanced Axion-Photon Coupling in a GUT with Hidden Photon 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      There is a novel way to achieve the gauge coupling unification with an unbroken hidden U(1) symmetry. In this case, a kinetic mixing and a hidden coupling are required to be large. Consequently, the axion-photon coupling is significantly enhanced if one employs the Peccei-Quinn solution to the strong CP-problem. We show that this enhanced coupling can be tested in various future experiments.

      Speaker: Norimi Yokozaki
    • 12:00 13:30
      Lunch 1h 30m
    • 13:30 14:00
      H-COUP: from v1 to v2 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      We introduce H-COUP, a program to calculate the Higgs couplings in various extended Higgs models, and discuss its application to compute the Higgs decay rates including higher-order corrections.

      Speaker: Dr Kentarou Mawatari (LPSC Grenoble)
    • 14:00 14:30
      Gravitational waves from first order electroweak phase transition in models with the U(1)_X gauge symmetry 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      In this talk, we consider the standard model extension with a dark sector with the $U(1)_X$ Abelian gauge symmetry, which is spontaneously broken by dark Higgs mechanism. We discuss patterns of the electroweak phase transition and detectability of gravitational waves (GWs) when strongly first order phase transition occurs. We find the collider bounds exclude a part of parameter space that could generate detectable GWs otherwise. We show that GWs produced in the multi-step phase transitions can be detected by future observations such as DECIGO and LISA. Furthermore, we discuss the complementarity of dark photon searches or dark matter searches with the GW observations in the models of the dark gauge symmetry. This talk is based on a collaboration with Katsuya Hashino, Shinya Kanemura, Mitsuru Kakizaki and Pyungwon Ko.

      Speaker: Toshinori Matsui
    • 14:30 15:00
      Probing first order phase transition by the combination of gravitational waves and Higgs couplings 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Electroweak baryogengesis is a scenario to explain baryon asymmetry of the universe. By the Sakharov conditions, the scenario requires strongly electroweak first order phase transition. For example, when two Higgs doublet model realizes strongly electroweak first order phase transition by thermal loop effects, triple Higgs boson coupling becomes large. On the other hand, if electroweak phase transition is first order, gravitational wave occurs by the phase transition.
      In this talk, we focus on extended Higgs sectors which realize electroweak first order phase transition. We discuss the testability of electroweak first order phase transition in the models by the combination of the precision measurements of Higgs boson couplings, the measurement of the triple Higgs boson coupling and the shape of the spectrum of gravitational wave.

      Speaker: Mr Katsuya Hashino
    • 15:00 15:30
      Break 30m
    • 15:30 16:00
      Theoretical improvements in particle dark matter searches 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Dark matter is one of the mysteries in the universe, and many experiments to discover the nature of dark matter are ongoing. Focusing on the theoretical aspects, I will discuss direct and indirect searches of dark matter.

      Speaker: Koji Ishiwata (Kanazawa University)
    • 16:00 16:30
      A new model for radiative Dirac neutrino masses with dark matter and electroweak baryogenesis 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Until now, various models to explain tiny neutrino mass have been proposed.
      Among them, it is known that a model proposed by M. Aoki, S. Kanemura and O. Seto can resolve not only neutrino oscillation but also dark matter and baryon asymmetry of the Universe. Although this model generates Majorana neutrino mass, we found a Dirac neutrino mass model, which can resolve these 3 phenomena, by classification of neutrino mass model in our previous study.
      In this talk, we show that there is a benchmark scenario which can simultaneously explain these 3 phenomena namely, neutrino oscillation, dark matter and baryon asymmetry of the Universe.

      Speaker: Kodai Sakurai
    • 16:30 17:00
      Break 30m
    • 17:00 17:30
      Dynamical scalegenesis via multiple seesaw mechanisms 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      We propose a model which accounts for the dynamical origin of the electroweak symmetry breaking (EWSB), directly linking to the mass generation of dark matter (DM) candidates and active neutrinos. The standard model (SM) is weakly charged under the U(1) B-L gauge symmetry, in conjunction with newly introduced three right-handed Majorana neutrinos and the B-L Higgs. The model is built on the classical scale invariance, that is dynamically broken by a new strongly coupled sector, that is called the hypercolor (HC) sector, which is also weakly coupled to the B-L gauge. At the HC strong scale, the simultaneous breaking of the EW and B-L gauge symmetries is triggered by dynamically induced multiple seesaw mechanisms, namely bosonic seesaw mechanisms. Thus, all of the origins of masses are provided singly by the HC dynamics: that is what we call the dynamical scalegenesis. We also find that a HC baryon, with a mass on the order of a few TeV, can be stabilized by the HC baryon number and the B-L charge, so identified as a DM candidate. The HC-baryon DM can be measured through the large magnetic moment coupling generated from the HC dynamics, or the B-L gauge boson portal in direct detection experiments.

      Speaker: Shohei Okawa (Nagoya University)
    • 17:30 18:00
      Migdal effect in Dark Matter Direct Detection Experiments 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Due to the negative results in dark matter search, people started to consider alternatives to the ordinary WIMP dark matter. In particular, they discuss a light dark matter having a mass less than a few GeV, which is difficult to detect in direct detection experiments. Recently, a new technique to detect such a light dark matter is proposed. It uses scintillation light from the inelastic scattering of an atom by a dark matter although the probability is very small. Since there had been no valid formulation of the process, we formulated it at the leading order and showed that the existing detectors already have sensitivity comparable to the current experimental limit.

      Speaker: Yutaro Shoji (University of Tokyo)
    • 19:30 21:30
      Banquet 2h Matsuya Honten

      Matsuya Honten

  • Wednesday, 17 January
    • 09:15 10:00
      Testing naturalness at the future collider 45m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      Solutions to the electroweak hierarchy problem typically introduce a new symmetry to stabilize the quadratic ultraviolet sensitivity in the self-energy of the Higgs boson. The new symmetry is either broken softly or collectively, as for example in supersymmetric and little Higgs theories. At low energies, such theories contain naturalness partners of the Standard Model fields which are responsible for canceling the quadratic divergence in the squared Higgs mass. Post the discovery of any partner-like particles, we propose to test the aforementioned cancellation by measuring relevant Higgs couplings. Using the fermionic top partners in little Higgs theories as an illustration, we construct a simplified model for naturalness and initiate a study on testing naturalness. After electroweak symmetry breaking, naturalness in the top sector requires aT = −λ2t at leading order, where λt and aT are the Higgs couplings to a pair of top quarks and top partners, respectively. Using a multivariate method of Boosted Decision Tree to tag boosted particles in the Standard Model, we show that, with a luminosity of 30ab−1 at a 100TeV pp-collider, naturalness could be tested with a precision of 10 % for a top partner mass up to 2.5 TeV.

      Speaker: Chuan-Ren Chen (National Taiwan Normal University)
    • 10:00 10:30
      Indirect test of extended Higgs model with CP-violation at the future collider 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      The baryon asymmetry of the universe that cannot be explained in the standard model may be explained by considering the extended Higgs model with CP-violation. In this talk, we focus on the two Higgs doublet model with CP-violation as a model that can realize the electroweak baryogenesis, and then we analyze indirect effect of CP-violation on the couplings of the discovered Higgs boson and discuss the test using the future colliders.

      Speaker: Mitsunori Kubota (University of Toyama)
    • 10:30 11:00
      Photo & Break 30m
    • 11:00 11:30
      Higgs inflation puts lower and upper bounds on tensor-to-scalar ratio and on Higgs-portal-dark-matter mass 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      We find a theoretical lower bound on the tensor-to-scalar ratio r from a premise that extrapolation of the Higgs-field direction plays the role of the inflaton at high scales. We assume that all the non-minimal couplings are not particularly large so that the renormalizable low-energy effective field theory is reliable up to 10^17GeV. This framework includes the so-called critical Higgs inflation. In our analysis, we take into account the Higgs-portal scalar dark matter and the heavy right-handed neutrinos. The resultant bounds are rather stringent. In particular in the absence of the right-handed neutrinos, namely, when the right-handed-neutrino masses are smaller than 10^13GeV, the Planck bound r<0.09 implies that the dark-matter mass must be smaller than 1.1TeV. On the other hand, the PandaX-II bound on the dark-matter mass m_DM>750GeV leads to r>4x10^-3. Both are within the range of near-future detection. When we include the right-handed neutrinos of mass M_R=10^14GeV, the allowed region becomes wider, but we still predict r>10^-3 in the most of the parameter space. The most conservative bound becomes r>10^-5 if we allow three-parameter tuning of m_DM, M_R, and the top-quark mass.

      Speaker: Kin-ya Oda (Osaka University)
    • 11:30 12:00
      Model independent evaluation of the Wilson coefficient of the Weinberg oparator in QCD 30m Tamokuteki-Hall (B243)

      Tamokuteki-Hall (B243)

      We derive a Wilson coefficient of a CP-violating purely gluonic dimension-6 operator called the Weinberg operator ($GG\tilde{G}$) generated by a scalar and two fermions at the two-loop level. We do not specify the representation of SU(3)$_c$ for the scalar and the fermions, and thus our result can be applied to a variety of models beyond the standard model. We estimate the nucleon EDMs induced by the Weinberg operator in some examples and discuss the importance of measuring EDMs. It is found that future measurements of the EDMs can probe physics at higher energy scale beyond the reach of collider experiments.

      Speaker: Dr Tomohiro Abe
    • 12:00 13:30
      Lunch & Room change to A238 1h 30m
    • 13:30 14:00
      Recent Kaon Anomaly 30m A238


      A new discrepancy between the standard model prediction and the experimental value was recently reported in the direct CP violation of the neutron Kaon decays.
      We study SUSY interpretations of this anomaly and discuss how to test the scenario in future experiments.

      Speaker: Motoi Endo (DESY)
    • 14:00 14:30
      LHCb anomaly and B physics in flavored Z' models with flavored Higgs doublets 30m A238


      We study an extended Standard Model with a gauged U(1)' flavor symmetry, motivated not only by the fermion mass hierarchy but also by the excesses in $B \to K^{(∗)}ll$ reported by the LHCb collaborations. The U(1)' charges are assigned to quarks and leptons in a flavor-dependent manner, and flavored Higgs doublets are also introduced in order to detail the Yukawa couplings at the renormalizable level. Then, the fermion mass hierarchy is realized by the vacuum alignment of the Higgs doublets. In this model, flavor-changing currents involving the gauge boson of U(1)' and the scalars generated by the Higgs doublets are predicted and the observables in the $B \to K^{(∗)}ll$ process possibly deviate from the Standard Model predictions. We study the possibility that these new flavor-changing interactions can explain the excesses in the $B \to K^{(∗)}ll$ process, and we derive some predictions for the other flavor-violating processes based on the analysis. We specifically investigate the $\Delta F=2$ processes and the other $B$ decays: e.g., $B \to X_s \gamma$ and $B \to D^{(∗)} \tau \nu$, where the deviations are reported by the Belle and $BABAR$ collaborations.

      Speaker: Yoshihiro Shigekami (Nagoya University)
    • 14:30 15:00
      Break 30m
    • 15:00 15:30
      The correction to the Fermi's golden rule: implication to particle physics and cosmology 30m A238


      The transition probability P(T) at the finite time interval,T, is determined by the wave functions and behaves as P(T)= \Gamma T+P^d, where \Gamma is derived from the golden rule and P^d is the correction term. P^d has been considered negligible since Dirac's time, but it was found recently that is not so, by series of studies of the present author and his collaborators. P^d has origin in many-body interaction energy, and has intriguing properties. It gives sizable effects in wide area, which are similar to background, and has not been paid attention by researchers. Origins and peculiar properties of P^d are explained, and some implications to particle physics and cosmology are given.

      Speaker: Prof. kenzo ISHIKAWA (Hokkaido University )
    • 15:30 16:00
      Relic abundance of the lightest Kaluza-Klein particle in phenomenological universal extra dimension models 30m A238


      We discuss the thermal relic abundance of the lightest Kaluza-Klein (KK) particle in phenomenological universal extra dimension models. We point out that its thermal relic abundance depends significantly on the mass degeneracy between the KK-photon and other KK particles because of considerable coannihilation effects.

      Speaker: Mitsuru Kakizaki (University of Toyama)