Dark matter in minimal supergravity with type-II seesaw

TL;DR

This paper investigates how the inclusion of a type-II seesaw mechanism in minimal supergravity models affects the relic density of neutralino dark matter, revealing spectrum deformations and new constraints from neutrino data and lepton flavor violation.

Contribution

It provides a detailed analysis of the impact of a triplet below the GUT scale on the sparticle spectrum and dark matter relic density in minimal supergravity models.

Findings

Triplet presence deforms the sparticle spectrum compared to pure mSugra.

Dark matter allowed regions vary with the seesaw scale.

Constraints from lepton flavor violation complement dark matter bounds.

Abstract

We calculate the relic density of the lightest neutralino in a supersymmetric seesaw type-II (``triplet seesaw'') model with minimal supergravity boundary conditions at the GUT scale. The presence of a triplet below the GUT scale, required to explain measured neutrino data in this setup, leads to a characteristic deformation of the sparticle spectrum with respect to the pure mSugra expectations, affecting the calculated relic dark matter (DM) density. We discuss how the DM allowed regions in the (m_0,M_{1/2}) plane change as a function of the (type-II) seesaw scale. We also compare the constraints imposed on the models parameter space form upper limits on lepton flavour violating (LFV) decays to those imposed by DM. Finally, we briefly comment on uncertainties in the calculation of the relic neutralino density due to uncertainties in the measured top and bottom masses.