Effect of Quark Scatter on Baryogenesis by Electroweak Strings
  The amount of baryon asymmetry generated by the electroweak strings at a rough estimate is smaller than that generated by the bubble expansion since the collapsing strings cannot cover the whole volume of the universe. However, the interaction cross section of the strings with particles can be larger than the geometrical area of the order of the string thickness. The scattering cross section of quarks from the electroweak strings is calculated using Dirac equation in the string background. It it proportional to the reverse of the momentum perpendicular to the string axis. Thus the effective interaction area can be enhanced at least ten times so that the suppression compared to the first order phase transition scenario might be also improved. 
Michiyasu Nagasawa (YITP, Kyoto University)