Cornering light Neutralino Dark Matter at the LHC

TL;DR

This paper assesses the constraints on light neutralino dark matter within the MSSM using recent LHC data, establishing a lower mass limit of about 24 GeV and projecting full testability up to 30 GeV with improved searches.

Contribution

It provides a reinterpretation of LHC electroweak supersymmetric particle searches to set new bounds on light neutralino dark matter within a simplified MSSM model.

Findings

Lower bound on neutralino mass is about 24 GeV.

Current LHC data surpasses underground dark matter search limits.

Potential to fully test neutralino masses up to 30 GeV with improved searches.

Abstract

We investigate the current status of the light neutralino dark matter scenario within the minimal supersymmetric standard model (MSSM) taking into account latest results from the LHC. A discussion of the relevant constraints, in particular from the dark matter relic abundance, leads us to a manageable simplified model defined by a subset of MSSM parameters. Within this simplified model we reinterpret a recent search for electroweak supersymmetric particle production based on a signature including multi-taus plus missing transverse momentum performed by the ATLAS collaboration. In this way we derive stringent constraints on the light neutralino parameter space. In combination with further experimental information from the LHC, such as dark matter searches in the monojet channel and constraints on invisible Higgs decays, we obtain a lower bound on the lightest neutralino mass of about 24 GeV. This limit is stronger than any current limit set by underground direct dark matter searches or indirect detection experiments. With a mild improvement of the sensitivity of the multi-tau search, light neutralino dark matter can be fully tested up to about 30 GeV.