Neutrino number asymmetry and cosmological birefringence

TL;DR

This paper explores how a CPT-even dimension-six Chern-Simons-like term, possibly from superstring theory, combined with neutrino asymmetry, can cause observable cosmological birefringence in CMB polarization data.

Contribution

It introduces a novel effective interaction model linking superstring-inspired terms and neutrino asymmetry to explain cosmological birefringence.

Findings

Neutrino asymmetry can induce significant polarization rotation.

The new term provides an alternative explanation for birefringence.

Potential observational signatures in CMB data.

Abstract

We study a new type of effective interactions in terms of the $CPT$-even dimension-six Chern-Simons-like term, which could originate from superstring theory, to generate the cosmological birefringence. We use the neutrino number asymmetry to induce a sizable rotation polarization angle in the data of the cosmic microwave background radiation polarization. The combined effect of the new term and the neutrino asymmetry provides an alternative way to understand the birefringence.