Cosmology of Gravitino LSP Scenario with Right-Handed Sneutrino NLSP

TL;DR

This paper explores a supersymmetric cosmological model with Dirac neutrino masses, where a gravitino LSP and right-handed sneutrino NLSP relax big-bang nucleosynthesis constraints and impact structure formation.

Contribution

It introduces a novel gravitino LSP scenario with right-handed sneutrino NLSP, analyzing its cosmological implications and constraints.

Findings

Cosmological constraints are significantly relaxed in this scenario.

Implications for structure formation are discussed.

Potential compatibility with observational data.

Abstract

We consider supersymmetric model with right-handed (s)neutrinos where the neutrino masses are purely Dirac-type. We discuss cosmology based on such a scenario, paying particular attention to the case that the gravitino is the lightest superparticles (LSP) while the right-handed sneutrino is the next-LSP. It will be shown that the cosmological constraints on the gravitino-LSP scenario (in particular, those from the big-bang nucleosynthesis) are drastically relaxed in such a case. We will also consider the implication of such scenario to the structure formation.