# Baryogenesis from axion inflation

## TL;DR

This paper presents a minimal baryogenesis model from axion inflation coupling to the Standard Model, where hyper magnetic fields and chiral fermions generate the observed baryon asymmetry without extra ingredients.

## Contribution

It introduces a predictive baryogenesis mechanism from axion inflation involving hyper magnetic fields and chiral fermions, requiring no beyond-Standard Model physics.

## Key findings

- The model can reproduce the observed baryon asymmetry under specific conditions.
- The baryon asymmetry depends on the inflation scale, around 10^{10} to 10^{12} GeV.
- The mechanism is highly sensitive to the helicity and chemical potential parameters.

## Abstract

The coupling of an axion-like particle driving inflation to the Standard Model particle content through a Chern-Simons term generically sources a dual production of massless helical gauge fields and chiral fermions. We demonstrate that the interplay of these two components results in a highly predictive baryogenesis model, which requires no further ingredients beyond the Standard Model. If the helicity stored in the hyper magnetic field and the effective chemical potential induced by the chiral fermion production are large enough to avoid magnetic diffusion from the thermal plasma but small enough to sufficiently delay the chiral plasma instability, then the non-vanishing helicity survives until the electroweak phase transition and sources a net baryon asymmetry which is in excellent agreement with the observed value. If any of these two conditions is violated, the final baryon asymmetry vanishes. The observed baryon asymmetry can be reproduced if the energy scale of inflation is around $H_\text{inf} \sim 10^{10}$ - $10^{12}$ GeV with a moderate dependence on inflation model parameters.