The 3rd Winter Toyama Mini-Workshop on Particle Physics and Cosmology "Basis of the Universe with Revolutionary Ideas 2018 (BURI2018)"
from
Tuesday, 16 January 2018 (08:00)
to
Wednesday, 17 January 2018 (16:00)
Monday, 15 January 2018
Tuesday, 16 January 2018
09:30
Registration
Registration
09:30 - 09:55
10:00
Announcement
-
Mitsuru Kakizaki
(
University of Toyama
)
Announcement
Mitsuru Kakizaki
(
University of Toyama
)
10:00 - 10:15
I will give a brief introduction.
10:15
Dark pion DM : WIMP vs. SIMP
-
Pyungwon Ko
Dark pion DM : WIMP vs. SIMP
Pyungwon Ko
10:15 - 11:00
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.
11:00
Realization of a spontaneous gauge and supersymmetry breaking vacuum
-
Yuji Omura
Realization of a spontaneous gauge and supersymmetry breaking vacuum
Yuji Omura
11:00 - 11:30
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.
11:30
Enhanced Axion-Photon Coupling in a GUT with Hidden Photon
-
Norimi Yokozaki
Enhanced Axion-Photon Coupling in a GUT with Hidden Photon
Norimi Yokozaki
11:30 - 12:00
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.
12:00
Lunch
Lunch
12:00 - 13:30
13:30
H-COUP: from v1 to v2
-
Kentarou Mawatari
(
LPSC Grenoble
)
H-COUP: from v1 to v2
Kentarou Mawatari
(
LPSC Grenoble
)
13:30 - 14:00
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.
14:00
Gravitational waves from first order electroweak phase transition in models with the U(1)_X gauge symmetry
-
Toshinori Matsui
Gravitational waves from first order electroweak phase transition in models with the U(1)_X gauge symmetry
Toshinori Matsui
14:00 - 14:30
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.
14:30
Probing first order phase transition by the combination of gravitational waves and Higgs couplings
-
Katsuya Hashino
Probing first order phase transition by the combination of gravitational waves and Higgs couplings
Katsuya Hashino
14:30 - 15:00
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.
15:00
Break
Break
15:00 - 15:30
15:30
Theoretical improvements in particle dark matter searches
-
Koji Ishiwata
(
Kanazawa University
)
Theoretical improvements in particle dark matter searches
Koji Ishiwata
(
Kanazawa University
)
15:30 - 16:00
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.
16:00
A new model for radiative Dirac neutrino masses with dark matter and electroweak baryogenesis
-
Kodai Sakurai
A new model for radiative Dirac neutrino masses with dark matter and electroweak baryogenesis
Kodai Sakurai
16:00 - 16:30
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.
16:30
Break
Break
16:30 - 17:00
17:00
Dynamical scalegenesis via multiple seesaw mechanisms
-
Shohei Okawa
(
Nagoya University
)
Dynamical scalegenesis via multiple seesaw mechanisms
Shohei Okawa
(
Nagoya University
)
17:00 - 17:30
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.
17:30
Migdal effect in Dark Matter Direct Detection Experiments
-
Yutaro Shoji
(
University of Tokyo
)
Migdal effect in Dark Matter Direct Detection Experiments
Yutaro Shoji
(
University of Tokyo
)
17:30 - 18:00
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.
19:30
Banquet
Banquet
19:30 - 21:30
Wednesday, 17 January 2018
09:15
Testing naturalness at the future collider
-
Chuan-Ren Chen
(
National Taiwan Normal University
)
Testing naturalness at the future collider
Chuan-Ren Chen
(
National Taiwan Normal University
)
09:15 - 10:00
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.
10:00
Indirect test of extended Higgs model with CP-violation at the future collider
-
Mitsunori Kubota
(
University of Toyama
)
Indirect test of extended Higgs model with CP-violation at the future collider
Mitsunori Kubota
(
University of Toyama
)
10:00 - 10:30
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.
10:30
Photo & Break
Photo & Break
10:30 - 11:00
11:00
Higgs inflation puts lower and upper bounds on tensor-to-scalar ratio and on Higgs-portal-dark-matter mass
-
Kin-ya Oda
(
Osaka University
)
Higgs inflation puts lower and upper bounds on tensor-to-scalar ratio and on Higgs-portal-dark-matter mass
Kin-ya Oda
(
Osaka University
)
11:00 - 11:30
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.
11:30
Model independent evaluation of the Wilson coefficient of the Weinberg oparator in QCD
-
Tomohiro Abe
Model independent evaluation of the Wilson coefficient of the Weinberg oparator in QCD
Tomohiro Abe
11:30 - 12:00
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.
12:00
Lunch & Room change to A238
Lunch & Room change to A238
12:00 - 13:30
13:30
Recent Kaon Anomaly
-
Motoi Endo
(
DESY
)
Recent Kaon Anomaly
Motoi Endo
(
DESY
)
13:30 - 14:00
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.
14:00
LHCb anomaly and B physics in flavored Z' models with flavored Higgs doublets
-
Yoshihiro Shigekami
(
Nagoya University
)
LHCb anomaly and B physics in flavored Z' models with flavored Higgs doublets
Yoshihiro Shigekami
(
Nagoya University
)
14:00 - 14:30
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.
14:30
Break
Break
14:30 - 15:00
15:00
The correction to the Fermi's golden rule: implication to particle physics and cosmology
-
kenzo ISHIKAWA
(
Hokkaido University
)
The correction to the Fermi's golden rule: implication to particle physics and cosmology
kenzo ISHIKAWA
(
Hokkaido University
)
15:00 - 15:30
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.
15:30
Relic abundance of the lightest Kaluza-Klein particle in phenomenological universal extra dimension models
-
Mitsuru Kakizaki
(
University of Toyama
)
Relic abundance of the lightest Kaluza-Klein particle in phenomenological universal extra dimension models
Mitsuru Kakizaki
(
University of Toyama
)
15:30 - 16:00
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.