CP violation in bilinear R-parity violation and its consequences for the early universe

TL;DR

This paper explores how CP violation in bilinear R-parity violating supersymmetric models influences neutrino masses, LSP decays, and the generation of the universe's matter-antimatter asymmetry, considering effects on early universe baryogenesis.

Contribution

It analyzes the impact of CP violation in BRpV models on neutrino physics and baryogenesis, including the role of light neutralino decays in generating matter asymmetry.

Findings

CP violation affects neutrino mass and mixing.

Light LSP decays can generate baryon asymmetry.

Asymmetries are reduced but still viable before electroweak transition.

Abstract

Supersymmetric models with bilinear R-parity violation (BRpV) provide a framework for neutrino masses and mixing angles to explain neutrino oscillation data. We consider CP violation within the new physical phases in BRpV and discuss their effect on the generation of neutrino masses and the decays of the lightest supersymmetric particle (LSP), being a light neutralino with mass $\sim 100$ GeV, at next-to-leading order. The decays affect the lepton and via sphaleron transitions the baryon asymmetry in the early universe. For a rather light LSP, asymmetries generated before the electroweak phase transition via e.g. the Affleck-Dine mechanism are reduced up to two orders of magnitude, but are still present. On the other hand, the decays of a light LSP themselves can account for the generation of a lepton and baryon asymmetry, the latter in accordance to the observation in our universe, since the smallness of the BRpV parameters allows for an out-of-equilibrium decay and sufficiently large CP violation is possible consistent with experimental bounds from the non-observation of electric dipole-moments.