Naturally Large Cosmological Neutrino Asymmetries in the MSSM

TL;DR

The paper proposes a theoretical framework within the MSSM where large neutrino asymmetries naturally arise, linking them to baryon asymmetries generated via the Affleck-Dine mechanism, with observable cosmological implications.

Contribution

It introduces a model connecting neutrino and baryon asymmetries through specific flat directions in the MSSM, explaining naturally large neutrino asymmetries.

Findings

Neutrino asymmetry can be naturally large in MSSM scenarios.

The ratio n_{L}/n_{B} is predicted to be in the range 10^{8}-10^{9}.

Observable neutrino asymmetries are correlated with baryon asymmetries around 10^{-10}.

Abstract

A large neutrino asymmetry is an interesting possibility for cosmology, which can have significant observable consequences for nucleosynthesis and the cosmic microwave background. However, although it is a possibility, there is no obvious reason to expect the neutrino asymmetry to be observably large. Here we note that if the baryon asymmetry originates via the Affleck-Dine mechanism along a d=4 flat direction of the MSSM scalar potential and if the lepton asymmetry originates via Affleck-Dine leptogenesis along a d=6 direction, corresponding to the lowest dimension directions conserving R-parity, then the ratio n_{L}/n_{B} is naturally in the range 10^{8}-10^{9}. As a result, a potentially observable neutrino asymmetry is correlated with a baryon asymmetry of the order of 10^{-10}.