List of Poster Presentations

Deviation of Yukawa Coupling in Gauge-Higgs Unification
Adachi, Yuki (Matsue College of Technology)
We study the deviation of yukawa coupling in the gauge-Higgs unification scenario from the Standard Model one. Taking into account the brane mass terms necessary for generating the flavor mixing and removing the exotic massless fermions, we derive an analytic formula determining the KK mass spectrum and yukawa coupling. Applying the obtained results to the tau and bottom yukawa couplings, we numerically calculate the ratio of the yukawa couplings in the gauge-Higgs unification and in the Standard Model.
New model of massive spin-2 particles in curved space-time
Akagi, Satoshi (Nagoya University)
Recently, the new interaction terms called the pseudo-linear terms that can be added to the Fierz-Pauli Lagrangian without inducing ghost-modes have been proposed. We consider the model by including the pseudo-linear terms to the Fierz-Pauli Lagrangian and we couple the model with extenal gravity. Then we find that the interaction terms without derivatives can be extended to the model in the curved space without excitation of ghost-modes. On the other hand, we find that the derivative interaction term induces a ghost-mode in general but new non-minimal couplings do not induce a ghost-mode. In this talk, I discuss the analysis of the extension to the pseudo-linear theory in the curved space.
Emergent Geometries from Strong Coupling Gauge Theories
Asano, Yuhma (Kyoto University)
We showed the emergence of geometries from gauge theories in terms of a gauge/gravity duality. The duality is the one between IIA supergravity solutions and SU(2|4) symmetric gauge theories, which are BMN model, N=8 SYM on R x S^2 and N=4 SYM on R x S^3/Z_k. Though the geometries were constructed on the gravity side, it had not been revealed how the geometries embed and emerge from the corresponding gauge theories. In this poster, I am going to explain that the corresponding geometries are realized as the solution of the saddle point equations in the gauge theories, and that the typical geometric scale is characterized by the range of the eigenvalue distribution.
Descriptions of inflation in scalar field theories, perfect fluid, and F(R) gravity
Bamba, Kazuharu (Leading Graduate School Promotion Center, Ochanomizu University)
We explore the descriptions for the three observables of the inflationary universe: (i) the spectral index of curvature perturbations, (ii) the tensor-to-scalar ratio, and (iii) the running of the spectral index, in the framework of scalar field theories, perfect fluid models, and F(R) gravity theories by using the methods of reconstruction. By comparing the descriptions of these three observables with the recent cosmological observations, we explicitly demonstrate that the inflationary universe represented in scalar field theories, perfect fluid models, and F(R) gravity theories can be consistent with the Planck results. [1] K. Bamba, S. Nojiri and S. D. Odintsov, Phys. Lett. B 737, 374 (2014) [arXiv:1406.2417 [hep-th]]. [2] K. Bamba, S. Nojiri, S. D. Odintsov and D. Sáez-Gómez, Phys. Rev. D 90, 124061 (2014) [arXiv:1410.3993 [hep-th]].
From Maxwell-Chern-Simons theory in AdS3 towards hydrodynamics in 1 + 1 dimensions
Fujita, Mitsutoshi (YITP, Kyoto University)
We study Abelian Maxwell-Chern-Simons theory in three-dimensional AdS black hole backgrounds for both integer and non-integer Chern-Simons coupling. Such theories can be derived from various string theory constructions, which we review in the present work. In particular we find exact solutions in the low frequency, low momentum limit, ω,k << T (hydrodynamic limit). Using the holographic principle, we translate our results into correlation functions of vector and scalar operators in the dual strongly coupled 1+1-dimensional quantum field theory with a chiral anomaly at non-zero temperature T. Starting from the conformal case we show applicability of the hydrodynamic limit and discuss extensions to the non-conformal case. Correlation functions in the conformal case are compared to an exact field theoretic computation.
The step scaling function of 2 flavor sextet SU(3) fermions
Hasenfratz, Anna (University of Colorado Boulder)
We investigate the discrete $\beta$ function of the 2-flavor SU(3) sextet model using the gradient flow scheme. This renormalized quantity should agree between different fermion formulations, offering a test of universality. Staggered fermion investigations suggest that the system is chirally broken, following earlier Schroedinger functional studies with Wilson fermions that were consistent with conformality. Our preliminary results, using improved Wilson fermions and the gradient flow RG scheme, is not consistent with the staggered fermion results. Considering the potential phenomenological impact of this model, it is important to resolve this disagreement.
The scalar mesons effects in skyrmion model
He, BingRan (Nagoya Univ.)
We construct a skyrmion model including a two-quark and a four-quark scalar mesons as well as the pion, rho and omega mesons within a framework of the hidden local symmetry. We investigate the effects of scalar mesons in the model, we show that the scalar mesons reduce the skyrmion mass.
The Born-Infeld gravity in the Palatini formalism and its application
Katsuragawa, Taishi (Nagoya University)
Born-Infeld gravity is a modified gravity motivated by the quantum gravity, which has the ability to get rid of the big bang and other singularities. The action is highly non-linear, and the ghost mode appears in the metric formalism although we can show that the ghost mode does not appear in the Palatini formalism. We investigate the FLRW universe with dust in this theory, and show that the Big Bang singularity does not always emerge but the scale factor can be bounced. We also consider the black holes and find that the black hole entropy is given by the same form as that in general relativity.
The Born-Infeld gravity in the Palatini formalism and the condition of the black hole formation
KOMADA, Meguru (Department of Physics, Nagoya University)
In recent years, many kinds of modified gravity theories are suggested to get over problems in the general relativity. We consider a kind of these theories ""Born-Infeld gravity in the Palatini formalism"" and apply this theory to the problem of the black hole formation by considering the spherically symmetric collapse of dust ball. We find the condition for the mass that the black hole horizon is formed. Furthermore, we find that the dust ball does not always collapse into a singularity even if the horizon is formed, where some object could remains. The behavior of the remnant seem to be similar to that of the quantum remnant object, which is called ""Planck star"".
Dynamical chiral symmetry breaking and weak nonperturbative renormalization group equation in gauge theory
Kumamoto, Shin-Ichiro (Kanazawa University)
We analyze the dynamical chiral symmetry breaking in gauge theory by using the nonperturbative renormalization group equation, which is a first order nonlinear partial differential equation (PDE). In case that the spontaneous chiral symmetry breaking occurs, the nonlinear PDE encounters some non-analytic singularities at the finite critical scale even though the initial function is continuous and smooth. Therefore there is no usual solution of the PDE beyond the critical scale. In this presentation, we newly introduce the notion of a weak solution, which is the global solution of the weak nonperturbative renormalization group equation. We show how to evaluate the physical quantities by using the weak solution in detail and explain the variational principle properties of the weak solution.
Lattice study of SU(3) gauge theory with four fundamental fermions
Kurachi, Masafumi (KMI, Nagoya University)
LatKMI collaboration has been studying SU(3) gauge theories with large numbers of fermion flavor (Nf) with the fundamental representation. Physical picture of the Nf=4 SU(3) gauge theory is expected to be qualitatively similar to the real-life QCD, and it it is very important to study Nf=4 physics to make a contrast to the physical picture of Nf=8, 12. In this presentation, I will show the results of our lattice simulations on the Nf=4 SU(3) gauge theory, including the results of the flavor singlet scalar mass measurement, and discuss the qualitative difference between Nf=4 and Nf=8, 12 SU(3) gauge theories.
New approach to the Dirac spectral density with applications
Kuti, Julius (UC San Diego) and Wong, Chik Him (University of Wuppertal)
A novel algorithm is introduced for the stochastic determination of the scale dependent continuous spectral density function and mode number distribution function of the lattice Dirac operator. Some applications, like the chiral condensate and the scale dependent anomalous mass dimension of the nf=2 sextet model, are presented.
GUT Scale Threshold Effect on Proton Decay
Kuwahara, Takumi (Nagoya Univ.)
The supersymmetric grand unified theories (SUSY GUTs) are the promising models beyond the standard model for particle physics. The standard SUSY GUTs predict that there exist the baryon-number violating processes, such as proton decay. It is important to estimate RGE effects on these processes in order to predict precise nucleon lifetime since there exists a large scale running between the GUT scale and 1GeV where the nucleon matrix elements are calculated. In this work, we have evaluated the GUT scale threshold corrections to the Wilson coefficients of the dimension-six baryon-number violating operators, and then we have estimated the effect of the threshold corrections on the decay rate in the minimal SUSY SU(5) GUT setup.
Thermodynamics in 8-flavor QCD
Miura, Kohtaroh (KMI, Nagoya University)
Recent lattice studies indicate that the 8-flavor QCD at zero temperature has a possibility to realize Walking Technicolor (WTC) Model, a viable candidate for physics beyond the standard model. In the scenario of WTC, the thermal phase transition in 8-flavor QCD is interpreted as electroweak phase transition, and of great interest with regards to the electroweak baryogenesis. LatKMI Collaboration has investigated a thermodynamic property of 8-flavor QCD, and we report the current status.
Flavor violating Z' in SO(10) SUSY GUT
Muramatsu, Yu (Nagoya University)
We show SO(10) SUSY GUT model in which Z' gauge boson induces tree-level flavor violating interactions. Some additional U(1)' symmetry induce flavor violating Z'. Grand unification group such as SO(10) symmetry includes additional U(1)' symmetry. But such U(1)' symmetry usually induces flavor conserving interactions. We show that the mechanism to realize Yukawa unification induces flavor violating Z'. Besides we discuss flavor signal in this model.
Tree level unitarity and the finiteness of electroweak oblique corrections
Nagai, Ryo (Nagoya University)
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 weak gauge bosons at the tree level (unitarity sum rules). It is shown that the unitarity sum rules require the tree level ρ parameter to be 1, without explicitly invoking the custodial symmetry arguments. The one-loop finiteness of the electroweak oblique corrections is automatically guaranteed once these unitarity sum rules are imposed among Higgs couplings. Severe constraints on the lightest Higgs coupling (125GeV Higgs coupling) and the mass of the second lightest Higgs boson are obtained from the unitarity and the results of the electroweak precision tests (oblique parameter measurements). These results are compared with the effective theory of the light Higgs boson, and we find simple relationships between the mass of the second lightest Higgs boson in our framework and the ultraviolet cutoff in the effective theory framework.
3d Seiberg duality with an adjoint matter from 4d duality
Nii, Keita (Nagoya University)
We study the Seiberg dualities with an adjoint matter for the U(N) and SU(N) gauge groups in three- and four-dimensions with four supercharges. We derive the three-dimensional duality from four-dimensional one by the dimensional reduction including the non-perturbative effect of the S1-compactification. In the U(N) case, we obtain the Kim-Park duality, which is known as a generalization of the Aharony duality including an adjoint matter. In the SU(N) case, we obtain the duality which follows from un-gauging the U(N) Kim-Park duality.
Delay of the transition to the pion condensation phase in asymmetric nuclear matter using a holographic QCD model
Nishihara, Hiroki (Nagoya University)
We study the asymmetric nuclear matter using a holographic QCD model by introducing a baryonic charge in the infrared boundary. We first show that, in the normal hadron phase, the predicted values of the symmetry energy and it's slope parameter are comparable with the empirical values. We find that the phase transition from the normal phase to the pion condensation phase is delayed compared with the pure mesonic matter: The critical chemical potential is larger than the pion mass which is obtained for the pure mesonic matter. We also show that, in the pion condensation phase, the pion contribution to the isospin number density increases with the chemical potential, while the baryonic contribution is almost constant.
Form factor effects in a Higgs portal pionic dark matter model
Okawa, Shohei (Nagoya University)
It is an interesting possibility that dark matter interacts the SM particles only through the Higgs portal. If we consider a QCD-like strong interaction in the hidden sector, the pseudo Nambu-Goldstone bosons resulting from the spontaneous chiral symmetry breaking are the lightest hadrons in the hidden sector and thus can be the dark matter, which we call the dark pions. In this presentation, we will show that the portal interaction between the Higgs and the dark pions is related to pion scalar form factor and the enhancement effects of the portal interaction by this form factor tend to relax the constraint on the dark matter mass.
Unification of SUSY breaking and GUT breaking
Omura, Yuji (Nagoya Univ.)
We build explicit supersymmetric unification models where grand unified gauge symmetry breaking and supersymmetry (SUSY) breaking are caused by the same sector. Besides, the SM-charged particles are also predicted by the symmetry breaking sector, and they give the soft SUSY breaking terms through the so-called gauge mediation. We investigate the mass spectrums in an explicit model with SU(5) and additional gauge groups, and discuss its phenomenological aspects. Especially, nonzero A-term and B-term are generated at one-loop level according to the mediation via the vector superfields, so that the electro-weak symmetry breaking and 125 GeV Higgs mass may be achieved by the large B-term and A-term even if the stop mass is around 1 TeV.
Finite-temperature study of eight-flavor SU(3) gauge theory
Schaich, David (Syracuse University)
Lattice explorations of the phase structure of strongly coupled gauge theories can provide important insight into the chiral dynamics of these systems. With the Lattice Strong Dynamics Collaboration we have investigated finite-temperature transitions of SU(3) gauge theory with Nf=8 light flavors on lattice volumes up to 48^3x24. In stark contrast to QCD, we find that these transitions run into a lattice phase before reaching the chiral limit. This indicates an absence of spontaneous chiral symmetry breaking even at fairly strong renormalized couplings g^2~20.
Schwinger-Dyson Study for Conformal/Walking Dynamics with UV and IR Cutoffs
Shibata, Akihiro (Computing Research Center, High Energy Accelerator Research Organization (KEK))
Motivated by recent study of lattice Monte Carlo simulations, we study conformal/walking dynamics in many flavor QCD by using Schwinger-Dyson (SD) equation for a two-loop ladder approximation with infrared (IR) and ultra violet (UV) cutoffs. In this presentation, we numerically and analytically investigate the IR- and UV- cutoff effects for the dynamical mass generation. We demonstrate that due to the IR cutoff the artificially suppression of the mass anomalous dimension, the fake conformality and so on. We further investigate the cutoff dependence of the mass anomalous dimension and give the SD-based formulas of a finite-size hyper scaling (FSHS). The formulas allow us to handle the difficulty in study on the finite volume lattice, and lead to the reliable $\gamma_m$ even in the presence of the IR-cutoff effects.
Sizable D-term contribution as a sigunature of E6×SU(2)F×U(1)A SUSY GUT model
Shigekami, Yoshihiro (Nagoya University)
We show that the sizable D-term contributions to the sfermion mass spectrum can be signatures of a certain grand unified theory (GUT), E6×SU(2)F×U(1)A GUT. Note that these D-term contributions destroy the degeneracy of sfermion masses among different generations in this model. This is different from previous works, which have argued for the D-term contributions, which destroy the degeneracy of masses only between sfermions with different quantum charges, as a signature of GUT with a larger rank unification group. Such D-terms are strongly constrained by the flavor-changing neutral current processes if the SUSY breaking scale is the weak scale. However, in E6×SU(2)F×U(1)A, a natural SUSY-type sfermion mass spectrum is obtained, and if the sfermion masses of third generation of 10 are larger than O(1TeV) to realize the 126 GeV Higgs and the other sfermion masses are O(10TeV), then a sizable D-term contribution is allowed. If these D-terms can be observed in future experiments, like the 100 TeV proton collider or muon collider, we may confirm the E6×SU(2)F×U(1)A GUT.