The Relic Neutralino Surface at a 100 TeV collider

TL;DR

This paper explores the potential of a 100 TeV collider to detect neutralino dark matter by mapping the parameter space, focusing on small mass splittings and collider signatures, thus advancing dark matter search strategies.

Contribution

It provides a detailed analysis of the MSSM neutralino parameter space relevant for dark matter, highlighting collider detection prospects at 100 TeV with specific focus on small mass splittings.

Findings

Future 100 TeV collider can discover neutralino mass splittings down to 1 GeV.

Thermal relic neutralino masses up to 1.5 TeV are accessible with sufficient luminosity.

Small mass differences lead to distinctive collider signatures with hard electroweak radiation.

Abstract

We map the parameter space for MSSM neutralino dark matter which freezes out to the observed relic abundance, in the limit that all superpartners except the neutralinos and charginos are decoupled. In this space of relic neutralinos, we show the dominant dark matter annihilation modes, the mass splittings among the electroweakinos, direct detection rates, and collider cross-sections. The mass difference between the dark matter and the next-to-lightest neutral and charged states is typically much less than electroweak gauge boson masses. With these small mass differences, the relic neutralino surface is accessible to a future 100 TeV hadron collider, which can discover inter-neutralino mass splittings down to 1 GeV and thermal relic dark matter neutralino masses up to 1.5 TeV with a few inverse attobarns of luminosity. This coverage is a direct consequence of the increased collider energy: the Standard Model events with missing transverse momentum in the TeV range have mostly hard electroweak radiation, distinct from the soft radiation shed in compressed electroweakino decays. We exploit this kinematic feature in final states including photons and leptons, tailored to the 100 TeV collider environment.