Baryon asymmetry generation in the electroweak theory. A lattice study

We study the baryon asymmetry generation within the framework of the standard electroweak theory. The assumed first order finite temperature phase transition to the spontaneously broken phase is simulated on the lattice. The Monte Carlo data suggest that the high temperature plasma is populated with gauge-Higgs fluctuations, which produce a change Q in the Chern-Simons number during the transition, thereby creating fermions due to the electroweak anomaly. We provide evidence and arguments in favour of a uniform distribution of Q. This being the case, the baryon asymmetry produced during the phase transition is large enough to explain the asymmetry observed today. (orig.)