Magnetogenesis from axion-SU(2) inflation

TL;DR

This paper proposes a new inflationary magnetogenesis mechanism linking non-Abelian gauge fields during inflation to observable intergalactic magnetic fields, consistent with gamma-ray observations.

Contribution

It introduces a novel model connecting Spectator Chromo Natural Inflation with the Standard Model's SU(2) sector, producing large-scale magnetic fields.

Findings

Magnetic fields with ~1 Mpc correlation length can be generated.

The model's magnetic field strength aligns with intergalactic magnetic field observations.

The mechanism is compatible with high-energy gamma-ray spectra from distant blazars.

Abstract

We describe a novel proposal for inflationary magnetogenesis by identifying the non-Abelian sector of Spectator Chromo Natural Inflation (SCNI) with the $\rm{SU(2)}_{\rm L}$ sector of the Standard Model. This mechanism relies on the recently discovered attractor of SCNI in the strong backreaction regime, where the gauge fields do not decay on super-horizon scales and their backreaction leads to a stable new trajectory for the rolling axion field. The large super-horizon gauge fields are partly transformed after the electroweak phase transition into electromagnetic fields. The strength and correlation length of the resulting helical magnetic fields depend on the inflationary Hubble scale and the details of the SCNI sector. For suitable parameter choices we show that the strength of the resulting magnetic fields having correlation lengths around $1\, {\rm {Mpc}}$ are consistent with the required intergalactic magnetic fields for explaining the spectra of high energy $\gamma$ rays from distant blazars.