Spontaneous baryosynthesis with large initial phase

Abstract

We numerically investigate particle production by a pseudo-Nambu-Goldstone boson (pNGB) in spontaneous baryogenesis, focusing on large initial misalignment angles. Our analysis confirms the established cubic dependence of the baryon asymmetry on the initial phase for small angles. However, this scaling breaks down for larger angles, with particle production saturating as the initial phase approaches $\pi$ in Minkowski spacetime.

Comments: Text revised, references updated, and a clarification added regarding the local dissipative approximation. Based on arXiv:2504.08868