Cosmological birefringence induced by neutrino current

TL;DR

This paper discusses a new mechanism involving neutrino asymmetry and a dimension-six Chern-Simons-like term to explain cosmological birefringence observed in cosmic microwave background polarization.

Contribution

It introduces a novel effective interaction model using a CPT-even dimension-six Chern-Simons-like term to generate cosmological birefringence.

Findings

Neutrino number asymmetry can induce polarization rotation.

The proposed model explains the observed birefringence.

The mechanism links neutrino physics with cosmic microwave background observations.

Abstract

We review our recent work on the cosmological birefringence. We propose a new type of effective interactions in terms of the $CPT$-even dimension-six Chern-Simons-like term to generate the cosmological birefringence. We use the neutrino number asymmetry to induce a non-zero rotation polarization angle in the data of the cosmic microwave background radiation polarization.