Inverse decays and the relic density of the sterile sneutrino

TL;DR

This paper investigates how inverse decay processes affect the relic density of sterile sneutrino dark matter in a supersymmetric seesaw model, revealing that these processes significantly reduce the relic density but it remains above observed levels.

Contribution

It introduces the consideration of inverse decays into relic density calculations for sterile sneutrinos, providing a more accurate analysis of their viability as dark matter candidates.

Findings

Inverse decays can suppress sneutrino relic density by several orders of magnitude.

The relic density remains larger than the observed dark matter density even after including inverse decays.

The relic density depends on parameters like the mu parameter, sneutrino mass, and neutrino Yukawa coupling.

Abstract

We consider a weak scale supersymmetric seesaw model where the Higgsino is the next-to-lightest supersymmetric particle and the right-handed sneutrino is the dark matter candidate. It is shown that, in this model, inverse decays, which had been previously neglected, may suppress the sneutrino relic density by several orders of magnitude. After including such processes and numerically solving the appropriate Boltzmann equation, we study the dependence of the relic density on the mu parameter, the sneutrino mass, and the neutrino Yukawa coupling. We find that, even though much smaller than in earlier calculations, the sneutrino relic density is still larger than the observed dark matter density.