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J. Kripfganz

Publications and source records attributed to J. Kripfganz.

12 recordsLinked to original sources
arXiv1996

Non-perturbative correlation masses in the hot electroweak phase

The effective action describing the long range fluctuations in the high temperature phase of the electroweak standard theory is a strongly coupled SU(2)-Higgs-model in three dimensions. We outline in detail a model in which the spatial correlation scales in this phase are calculated as inverse relativistic bound state masses. Selection rules for these states are derived. The correlation masses are calculated by evaluating the bound state Green's function. The scalar-scalar-potential and its influence on the masses is investigated. The predictions for the correlation masses agree very well with the lattice data available now.

hep-ph↗
arXiv1996

Physics of the Electroweak Phase Transition at M_H <= 70 GeV in a 3-dimensional SU(2)-Higgs Model

Physical parameters of the electroweak phase transition in a 3d effective lattice SU(2)-Higgs model are presented. The phase transition temperatures, latent heats and continuum condensate discontinuities are measured at Higgs masses of about 70 and 35 GeV. Masses and Higgs condensates are compared to perturbation theory in the broken phase. In the symmetric phase bound states and the static force are determined.

hep-lat↗
arXiv1996

3--Dimensional Lattice Studies of the Electroweak Phase Transition at M_{Higgs} approx 70 GeV

We study the electroweak phase transition by lattice simulations of an effective 3--dimensional theory, for a Higgs mass of about 70 GeV. Exploiting, among others, a variant of the equal weight criterion of phase equilibrium, we obtain transition temperature, latent heat and surface tension, and compare with M_H approx 35 GeV. In the broken phase masses and Higgs condensates are compared to perturbation theory. For the symmetric phase, bound state masses and the static force are determined.

hep-lat↗
arXiv1995

Perturbative Contributions to the Electroweak Interface Tension

The main perturbative contribution to the free energy of an electroweak interface is due to the effective potential and the tree level kinetic term. The derivative corrections are investigated with one-loop perturbation theory. The action is treated in derivative, in heat kernel, and in a multi local expansion. The massive contributions turn out to be well described by the Z-factor. The massless mode, plagued by infrared problems, is numerically less important. Its perturbatively reliable part can by calculated in derivative expansion as well. A self consistent way to include the Z-factor in the formula for the interface tension is presented.

hep-ph↗
arXiv1995

$3$--Dimensional Approach to Hot Electroweak Matter for $M_{Higgs} \leq 70$ GeV

We study the electroweak phase transition by lattice simulations of an effective 3-dimensional theory, for a Higgs mass of about $70$ GeV. Exploiting a variant of the equal weight criterion of phase equilibrium, we obtain transition temperature, latent heat and surface tension and compare with $M_H \approx 35$ GeV. For the symmetric phase, bound state masses and the static force are determined and compared with results for pure $SU(2)$ theory.

hep-lat↗
arXiv1995

Bound States in the Hot Electroweak Phase

The high temperature phase of the electroweak standard theory is described by a strongly coupled SU(2)-Higgs-model in three dimensions. As in the Abbott-Farhi-model Higgs and W-boson are low lying bound states. Using a method by Simonov based on the Feynman-Schwinger representation of correlators we calculate the masses of these states. Our results are compared with lattice masses.

hep-ph↗
arXiv1995

3-D lattice simulation of the electroweak phase transition at small Higgs mass

We study the electroweak phase transition by lattice simulations of an effective 3-dimensional theory, for a Higgs mass of about $35 GeV$. In the broken symmetry phase our results on masses and the Higgs condensate are consistent with 2-loop perturbative results. However, we find a non-perturbative lowering of the transition temperature, similar to the one previously found at $m_H = 80 GeV$. For the symmetric phase, bound state masses and the static force are determined and compared with results for pure $SU(2)$ theory.

hep-lat↗
arXiv1994

Critical Bubbles and Fluctuations at the Electroweak Phase Transition

We discuss the critical bubbles of the electroweak phase transition using an effective high-temperature 3-dimensional action for the Higgs field $φ$. The separate integration of gauge and Goldstone boson degrees of freedom is conveniently described in the 't Hooft-Feynman covariant background gauge. The effective dimensionless gauge coupling $g_3(T)^2$ in the broken phase is well behaved throughout the phase transition. However, the behavior of the one-loop $Z(φ)$ factors of the Higgs and gauge kinetic terms signalizes the breakdown of the derivative expansion and of the perturbative expansion for a range of small $φ$ values increasing with the Higgs mass $m_H$. Taking a functional $S_z[φ]$ with constant $Z(φ)=z$ instead of the full non-local effective action in some neighborhood of the saddlepoint we are calculating the critical bubbles for several temperatures. The fluctuation determinant is calculated to high accuracy using a variant of the heat kernel method. It gives a strong suppression of the transition rate compared to previous estimates.

hep-ph↗
arXiv1994

Baryon Asymmetry from a Two Stage Electroweak Phase Transition ?

We investigate an extension of the standard model with a second Higgs doublet, showing a two stage phase transition. Wash-out of a baryon asymmetry after the phase transition can be easily avoided in this class of models. B+L transitions are more strongly suppressed in the intermediate phase than in the high temperature symmetric phase,however. Therefore, it becomes more difficult if not impossible to generate a sufficient baryon asymmetry during the phase transition.

hep-ph↗