Discovering Inelastic Thermal-Relic Dark Matter at Colliders

TL;DR

This paper proposes collider-based search strategies for inelastic dark matter, demonstrating that current and future experiments can probe significant parts of the thermal-relic parameter space, especially for masses between 100 MeV and 100 GeV.

Contribution

It introduces new collider search methods specifically targeting inelastic dark matter interactions, expanding the experimental reach for thermal-relic dark matter models.

Findings

LHC and BaBar can probe dark matter masses 100 MeV-100 GeV with certain splittings.

Future Belle II searches could access sub-GeV dark matter with dedicated triggers.

Large mass or splitting scenarios are largely excluded by current data.

Abstract

Dark Matter particles with inelastic interactions are ubiquitous in extensions of the Standard Model, yet remain challenging to fully probe with existing strategies. We propose a series of powerful searches at hadron and lepton colliders that are sensitive to inelastic dark matter dynamics. In representative models featuring either a massive dark photon or a magnetic dipole interaction, we find that the LHC and BaBar could offer strong sensitivity to the thermal-relic dark matter parameter space for dark matter masses between ~100 MeV-100 GeV and fractional mass-splittings above the percent level; future searches at Belle II with a dedicated monophoton trigger could also offer sensitivity to thermal-relic scenarios with masses below a few GeV. Thermal scenarios with either larger masses or splittings are largely ruled out; lower masses remain viable yet may be accessible with other search strategies.