New signatures of Dirac neutralino dark matter

TL;DR

This paper explores the unique signatures of Dirac neutralino dark matter in the MDGSSM, highlighting the presence of long-lived particles and their implications for LHC searches, expanding the understanding of supersymmetric dark matter phenomenology.

Contribution

It characterizes the parameter space of the MDGSSM where the lightest neutralino is a viable dark matter candidate and identifies regions with long-lived particles that current LHC searches do not cover.

Findings

Viable dark matter regions with long-lived neutralinos identified.

Small mass splittings lead to long-lived particles detectable at colliders.

Current LHC searches are insensitive to some long-lived neutralino scenarios.

Abstract

Supersymmetric dark matter has been studied extensively in the context of the MSSM, where gauginos have Majorana masses. Introducing Dirac gaugino masses, we obtain an enriched phenomenology from which considerable differences in, e.g., LHC signatures can be expected. Concretely, in the Minimal Dirac Gaugino Model (MDGSSM) we have an electroweakino sector extended by two extra neutralinos and one extra chargino. The bino- and wino-like states bring about small mass splittings leading to the frequent presence of scenarios with Long Lived Particles (LLPs). In this contribution, we delineate the parameter space of the electroweakino sector of the MDGSSM, where the lightest neutralino is a viable dark matter candidate that escapes current dark matter direct detection. We then focus on the allowed regions that contain LLPs and confront them against the corresponding LHC searches. Finally, we discuss the predominant case of long-lived neutralinos, to which no search is currently sensitive.