Bulk Mass Effects in Gauge-Higgs Unification at Finite Temperature

We study the bulk mass effects on the electroweak phase transition at finite temperature in a five dimensional SU(3) gauge-Higgs unification model on an orbifold. We investigate whether the Higgs mass satisfying the experimental lower bound can be compatible with the strong first order phase transition necessary for a successful electroweak baryogenesis. Our numerical results show that the above statement can be realized by matter with bulk mass yielding a viable Higgs mass. We also find an interesting case where the heavier Higgs gives the stronger first order phase transition.Comment: 17 pages, 1 figur

Chiral Charge Flux and Electroweak Baryogenesis

By treating CP-violating interaction of the electroweak bubble wall as a perturbative term, chiral charge flux through the bubble wall is estimated. It is found that the absolute value of the flux $F_Q$ has a sharp peak at $m_0 \sim a \sim T$ with $F_Q/(u T^3) \sim 10^{-3}\, (Q_L-Q_R)\,\Delta \theta$. Here $m_0$ is the fermion mass, $1/a$ is the wall thickness, $T$ is the temperature at which the bubbles are growing, $u$ is the wall velocity, $Q_{L(R)}$ is the chiral charge of the relevant left(right)-handed fermion and $\Delta\theta$ is the measure of CP violation.Comment: 10 pages, 4 figures ( not included, hard copies are available upon request ), plain TeX with phyzzx

Gauge Symmetry Breaking through the Hosotani Mechanism in Softly Broken Supersymmetric QCD

Gauge symmetry breaking through the Hosotani mechanism (the dynamics of nonintegrable phases) in softly broken supersymmetric QCD with $N_F^{fd}$ flavors is studied. For $N=$ even, there is a single SU(N) symmetric vacuum state, while for $N=$ odd, there is a doubly degenerate SU(N) symmetric vacuum state in the model. We also study generalized supersymmetric QCD by adding $N_F^{adj}$ numbers of massless adjoint matter. The gauge symmetry breaking pattern such as $SU(3)\to SU(2)\times U(1)$ is possible for appropriate choices of the matter content and values of the supersymmetry breaking parameter. The massless state of the adjoint Higgs scalar is also discussed in the models.Comment: 19 pages, no figure, final version to appear in Phys. Rev.

Dynamics of Nonintegrable Phases in Softly Broken Supersymmetric Gauge Theory with Massless Adjoint Matter

We study SU(N) supersymmetric Yang-Mills theory with massless adjoint matter defined on $M^3\otimes S^1$. The SU(N) gauge symmetry is broken maximally to $U(1)^{N-1}$, independent of the number of flavor and the boundary conditions of the fields associated with the Scherk-Schwarz mechanism of supersymmetry breaking. The mass of the Higgs scalar is generated through quantum corrections in the extra dimensions. The quantum correction can become manifest by a finite Higgs boson mass at low energies even in the limit of small extra dimensions thanks to the supersymmetry breaking parameter of the Scherk-Schwarz mechanism.Comment: 19 pages, 2 figures, corrected some typo

Aspects of Phase Transition in Gauge-Higgs Unification at Finite Temperature

We study the phase transition in gauge-Higgs unification at finite temperature. In particular, we obtain the strong first order electroweak phase transition for a simple matter content yielding the correct order of Higgs mass at zero temperature. Two stage phase transition is found for a particular matter content, which is the strong first order at each stage. We further study supersymmetric gauge models with the Scherk-Schwarz supersymmetry breaking. We again observe the first order electroweak phase transition and multi stage phase transition.Comment: 18 pages, 7 figures, references corrected, minor correctio

CP-violating profile of the electroweak bubble wall

In any scenario of the electroweak baryogenesis, the profile of the CP violating bubble wall, created at the first-order phase transition, plays an essential role. We attempt to determine it by solving the equations of motion for the scalars in the two-Higgs-doublet model at the transition temperature. According to the parameters in the potential, we found three solutions. Two of them smoothly connect the CP-violating broken phase and the symmetric phase, while the other connects CP-conserving vacua but violates CP in the intermediate region. We also estimate the chiral charge flux, which will be turned into the baryon density in the symmetric phase by the sphaleron process

Fermion Scattering off CP-Violating Electroweak Bubble Wall

A general prescription to solve the Dirac equation in the presence of CP-violating electroweak bubble wall is presented. The profile of the bubble wall is not specified except that the wall height is $m_0$ and zero deep in the broken- and the symmetric-phase regions, respectively, where $m_0$ is a fermion mass given by the Higgs-vacuum-expectation value and the Yukawa coupling. The CP-violating effects are evaluated by regarding CP-violating part of the bubble wall as a perturbation to CP-conserving solutions. The basic quantity, $R_{R\rightarrow L}-\bar R_{R\rightarrow L}$, which would contribute to the cosmological baryon asymmetry, is estimated for some typical profiles of the wall, where $R_{R\rightarrow L}$($\bar R_{R\rightarrow L}$) is the reflection coefficient of right-handed chiral fermion (anti-fermion).Comment: 30 pages, 2 figures ( uuencoded tar.Z file of PS files is appended ), plain TeX with phyzzx, tables and epsf,SAGA-HE-55--KYUSHU-HET-1