Charge Generation in the Oscillating Background

The preheating after the inflation, which can be interpreted as particle creation in the oscillating inflaton background, provides a state far from thermal equilibrium. We extend the field theoretical treatment of the preheating by Linde et al. to the case of multicomponent complex scalars to show that some charges are created in this process, if C and CP are violated. A new possibility of baryogenesis based on this mechanism is also discussed.Comment: 18 pages, LaTeX 2e, 3 eps figure

Electroweak phase transition in the MSSM with four generations

By assuming the existence of the sequential fourth generation to the minimal supersymmetric standard model (MSSM), we study the possibility of a strongly first-order electroweak phase transition. We find that there is a parameter region of the MSSM where the electroweak phase transition is strongly first order. In that parameter region, the mass of the lighter scalar Higgs boson is calculated to be above the experimental lower bound, and the scalar quarks of the third and the fourth generations are heavier than the corresponding quarks.Comment: 12 pages, 2 tables, 2 figure

Numerical Approach to CP-Violating Dirac Equation

We propose a new method to evaluate the chiral charge flux, which is converted into baryon number in the framework of the charge transport scenario of electroweak baryogenesis. By the new method, one can calculate the flux in the background of any type of bubble wall with any desired accuracy.Comment: 14 pages, epsf.sty is needed, 3 figures appende

CP Violating Bubble Wall and Electroweak Baryogenesis

The electroweak baryogenesis depends on the profile of the CP-violating bubble wall created at the first order phase transition. We attempt to determine it by solving the coupled equations of motion for the moduli and phases of the two Higgs doublets at the transition temperature. A variety of CP-violating bubble walls are classified by boundary conditions. We point out that a sufficiently small explicit CP violation gives nonperturbative effects to yield the baryon asymmetry of the universe.Comment: 19 pages, 6 EPS figures, uses epsf.st

Spontaneous CP Violation at Finite Temperature in the MSSM

By studying the effective potential of the MSSM at finite temperature, we find that CP can be spontaneously broken in the intermediate region between the symmetric and broken phases separated by the bubble wall created at the phase transition. This type of CP violation is necessary to have a bubble wall profile connecting CP conserving vacua, while violating CP halfway and generating sufficient baryon number without contradiction to the experimantal bounds on CP violations. Several conditions on the parameters in the MSSM are found for CP to be broken in this manner.Comment: 26 pages, LaTeX, 16 eps figures (epsf.sty is needed

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

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

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