Direct-detection constraints on inelastic dark matter with a scalar mediator

TL;DR

This paper investigates constraints on inelastic dark matter with a scalar mediator using data from xenon-based direct detection experiments, highlighting the impact of velocity suppression and mass splitting on detectability.

Contribution

It provides new constraints on scalar-mediated inelastic Dirac dark matter in the MeV-GeV mass range using public xenon experiment data.

Findings

Xenon experiments constrain sub-MeV mass splitting in inelastic DM.

Velocity suppression affects annihilation cross section and detection prospects.

Public data from XENON1T, PandaX-4T, and LZ are used to derive limits.

Abstract

We calculate direct detection constraints on inelastic dark matter (DM) for a scalar portal scenario with leptophilic couplings. The p-wave velocity suppression of the annihilation cross section of scalar-mediated inelastic Dirac DM implies the opening of viable regions of DM parameter space in the MeV-GeV mass range. Xenon-based experiments can provide a constraints on scalar-mediated inelastic fermion dark matter for sub-MeV mass splitting, via endothermic and exothermic spin-independent DM-electron scattering. To estimate the relevant constraints, we use public data from the XENON1T, PandaX-4T, and LZ liquid-xenon experiments that measure ionization electron signals.