Baryon production from embedded metastable strings

TL;DR

This paper investigates how metastable cosmic strings can produce baryons through skyrmion formation mediated by instantons, quantifying the production rate and implications for dense string networks in the early universe.

Contribution

It introduces a detailed model of skyrmion production from metastable strings in a thermal bath, linking topological defects to baryon generation in cosmology.

Findings

Quantified skyrmion production per unit length of the string.

Analyzed skyrmion-anti skyrmion production in dense string networks.

Demonstrated the role of quantum tunneling in core melting of metastable strings.

Abstract

We quantify the baryon anti-baryon production generated by a metastable cosmic string, similar to the embedded pion string. More precisely, we study skyrmion production mediated by instantons generated by a pion-like metastable string in contact with a thermal bath, and interpret these Skyrmions as baryons. As shown in a previous work, the core of such a metastable string can melt due to quantum tunneling in the charged field direction. The specific configuration of our string containing 4 scalar fields out of equilibrium in contact with a thermal bath is shown to yield skyrmion production with partial or integer winding number. In this work, we describe and quantify this skyrmion production per unit length of the string. We also evaluate the skyrmion-anti skyrmions production by a dense string network by invoking similarity with the Skyrmion production in a phase transition.