# Standard Model Baryon Number Violation at Zero Temperature from Higgs Bubble Collisions

## TL;DR

This paper calculates baryon number violation from Higgs bubble collisions at zero temperature, showing it can match thermal sphaleron rates, with implications for baryogenesis.

## Contribution

First computation of baryon number violation at zero temperature from Higgs bubble collisions using large-scale lattice simulations.

## Key findings

- Baryon violation rate comparable to thermal sphalerons at electroweak temperatures.
- Dependence of transition rates on scalar potential shape and bubble wall Lorentz factor.
- Estimated baryon asymmetry assuming CP violation during phase transition.

## Abstract

We compute for the first time baryon number violation at zero temperature from Higgs bubble collisions and find that it can be of the same order as that from thermal sphalerons in the symmetric phase at electroweak temperatures. We study the dependence of the rate of Chern--Simons number transitions on the shape of the scalar potential and on the Lorentz factor of the bubble walls at collision via large-scale (3+1)D lattice simulations of the Higgs doublet and SU(2) gauge fields. We estimate the resulting baryon asymmetry assuming some CP-violating source activated by the Higgs-field variation during the phase transition.