Impact of hypermagnetic fields on relic gravitational waves, neutrino oscillations and baryon asymmetry

TL;DR

This paper investigates how hypermagnetic fields in the early universe influence relic gravitational waves, neutrino oscillations, and baryon asymmetry, providing new constraints on seed magnetic field strengths based on observational data.

Contribution

It introduces a comprehensive model of hypermagnetic field evolution incorporating turbulence and dynamo effects, linking these to gravitational wave production and baryon asymmetry constraints.

Findings

Established upper bounds on seed hypermagnetic fields from gravitational wave observations.

Linked hypermagnetic field strength to baryon asymmetry constraints.

Analyzed the impact of hypermagnetic fields on neutrino flavor oscillations.

Abstract

We study the evolution of random hypermagnetic fields (HMFs) in the symmetric phase of the early universe before the electroweak phase transition. The behavior of HMFs is driven by the analog of the chiral magnetic effect accounting for the asymmetries of leptons and Higgs bosons. These asymmetries are also dynamical variables of the model and evolve together with HMFs. Moreover, we account for the contribution of the hyper-MHD turbulence in the effective diffusion coefficient and the $\alpha$-dynamo parameter. The realistic spectrum of seed HMFs consists of two branches: Batchelor and Kolmogorov ones. The impact of HMFs on the production of relic gravitational waves (GWs) and the baryon asymmetry of the universe (BAU), as well as flavor oscillations of supernova neutrinos in the stochastic GWs generated, are considered. We establish the constraint on the strength of the seed HMF comparing the spectral density of produced GWs with the observations of the LIGO-Virgo-KAGRA collaborations. The stronger upper bound on the seed HMF is obtained from the condition of not exceeding the observed value of BAU.