Revisiting light neutralino scenarios in the MSSM

TL;DR

This paper reevaluates light neutralino dark matter scenarios in the MSSM, showing that those relying on light pseudoscalar exchange are excluded, but light slepton scenarios remain viable with a minimum LSP mass of 12.6 GeV.

Contribution

It provides a comprehensive analysis of light neutralino scenarios in the MSSM, identifying viable models with light sleptons that satisfy current experimental constraints.

Findings

Light pseudoscalar exchange scenarios are excluded by current searches.

Viable light neutralino scenarios involve light sleptons with LSP mass ≥ 12.6 GeV.

Future LHC searches will further probe these models.

Abstract

We revisit the case of a light neutralino LSP in the framework of the MSSM. We consider a model with eleven free parameters. We show that all scenarios where the annihilation of light neutralinos rely mainly on the exchange of a light pseudoscalar are excluded by direct detection searches and by Fermi measurements of the gamma-flux from dwarf spheroidal galaxies. On the other hand, we find scenarios with light sleptons that satisfy all collider and astroparticle physics constraints. In this case, the lower limit on the LSP mass is 12.6 GeV. We discuss how the parameter space of the model will be further probed by new physics searches at the LHC.