arXiv subjects

Taizo Muta

Publications and source records attributed to Taizo Muta.

8 recordsLinked to original sources

arXiv2003

Dynamical origin of low-mass fermions in Randall-Sundrum background

We investigate a dynamical mechanism to generate fermion mass in the Randall-Sundrum background. We consider four-fermion interaction models where the fermion field propagates in an extra-dimension, i.e. the bulk four-fermion interaction model. It is assumed that two types of fermions with opposite parity exist in the bulk. We show that electroweak-scale mass is dynamically generated for a specific fermion anti-fermion condensation, even if all the scale parameters in the Lagrangian are set to the Planck scale.

hep-ph↗

arXiv2001

Dynamical Fermion Masses Under the Influence of Kaluza-Klein Fermions in Randall-Sundrum Background

The dynamical fermion mass generation on the D3-brane in the Randall-Sundrum space-time is discussed in a model with bulk fermions in interaction with fermions on the branes. It is found that the dynamical fermion masses are generated at the natural (R.-S.) radius of the compactified extra space and may be made small compared with masses of the Kaluza-Klein modes which is of order of TeV.

hep-ph↗

arXiv2000

$B\to ππ, K π$ Decays in QCD Improved Factorization Approach

Motivated by recent measurements, we investigate $B\to ππ, K π$ decay modes in the framework of QCD improved factorization, which was recently proposed by Beneke $et al$. We find that all the measured branching ratios are well accommodated in the reasonable parameter space except for $B\to K^0 π^0 $. We also discuss in detail the strong penguin contributions and the ${\cal O}(α_s)$ corrections to the chirally enhanced terms. We find that the weak phase $γ$ lies in the region $120^{\circ}<γ<240^{\circ}$, which is mainly constrained by $B\to π^- π^+ $.

hep-ph↗

arXiv2000

Dynamical fermion masses under the influence of Kaluza-Klein fermions in extra dimensions

The dynamical fermion mass generation in the 4-dimensional brane is discussed in a model with 5-dimensional Kaluza-Klein fermions in interaction with 4-dimensional fermions. It is found that the dynamical fermion masses are generated beyond the critical radius of the compactified extra dimensional space and may be made small compared with masses of the Kaluza-Klein modes.

hep-ph↗

arXiv1999

$η'-g^*-g$ Transition Form Factor with Gluon Content Contribution Tested

We study the $η'-g^*-g$ transition form factor by using the $η'$ wave function constrained by the experimental data on the $η'-γ^*-γ$ transition form factor provided by CLEO and L3 . We also take into account the contribution of the possible gluonic content of the $η'$ meson.

hep-ph↗

arXiv1999

Structure of Chiral Phase Transitions at Finite Temperature in Abelian Gauge Theories

The mechanism of the chiral symmetry breaking is investigated in the strong-coupling Abelian gauge theories at finite temperature. The Schwinger-Dyson equation in Landau gauge is employed in the real time formalism and is solved numerically within the framework of the instantaneous exchange approximation including the effect of the hard thermal loop for the photon propagator. It is found that the chiral symmetry is broken below the critical temperature T for sufficiently large coupling. The chiral phase transition is found to be of the 2nd order and the phase diagram on the $T-α$ plane is obtained. It is investigated how the structure of the chiral phase transition is affected by the hard thermal loops in the photon propagator.

hep-ph↗

arXiv1999

QCD Anomaly Coupling for the $η'-g-g$ Vertex in Inclusive Decay $B\toη' X_s$

The QCD anomaly coupling of $η'-g-g$ is treated as the axial vector current triangle anomaly. By assuming the divergent axial vector coupling of the $η'$ meson with the quark line in the triangle diagram, we calculate the QCD anomaly of $η'-g-g$ as well as the QED anomaly of $η'-γ-γ$ with only one common parameter $κ_{η'}$. We obtain consistent results of the branching ratios for $B\toη' X_s, J/ψ\toη'γ$ and $η'\to γγ$ when comparing with experimental data.

hep-ph↗

arXiv1997

Finite Grand Unified Theories and Inflation

A class of finite GUTs in curved spacetime is considered in connection with the cosmological inflation scenario. It is confirmed that the use of the running scalar-gravitational coupling constant in these models helps realizing a successful chaotic inflation. The analyses are made for some different sets of the models.

hep-ph↗