Electroweak Baryogenesis with Cosmic Strings ?

TL;DR

This paper critically examines the viability of electroweak baryogenesis mediated by cosmic strings, concluding that the generated baryon asymmetry is far too small to account for observations.

Contribution

It provides a detailed analysis of sphaleron rates and baryogenesis efficiency around cosmic strings, demonstrating the scenario's insufficiency.

Findings

Baryon asymmetry generated is at least 10 orders of magnitude too small.

Sphaleron rates inside cosmic strings are insufficient for effective baryogenesis.

The scenario faces significant theoretical challenges to explain observed matter-antimatter asymmetry.

Abstract

I report on a critical analysis of the scenario of electroweak baryogenesis mediated by nonsuperconducting cosmic strings. This mechanism relies upon electroweak symmetry restoration in a region around cosmic strings, where sphalerons would be unsuppressed. I discuss the various problems this scenario has to face, presenting a careful computation of the sphaleron rates inside the strings, of the chemical potential for chiral number and of the efficiency of baryogenesis in different regimes of string networks. The conclusion is that the asymmetry in baryon number generated by this scenario is smaller than the observed value by at least 10 orders of magnitude.