Self-interacting Dark Matter Without Direct Detection Constraints

TL;DR

This paper investigates a dark matter model where a small mass splitting in a dark photon interaction allows evasion of direct detection constraints, while maintaining detectable signals at colliders.

Contribution

It introduces a pseudo-Dirac dark matter model with a mass splitting that reduces direct detection constraints and explores its collider phenomenology.

Findings

Mass splitting weakens direct detection signals.

A viable parameter space exists for collider detection.

Dark matter mass window accessible to LHC and future colliders.

Abstract

We explore the self-interacting dark matter scenario in a simple dark sector model where the dark matter interacts through a dark photon. Splitting a Dirac fermion dark matter into two levels using a small Majorana mass can evade strong direct detection constraints on the kinetic mixing between the dark and normal photons, thus allowing the dark sector to be more visible at high intensity and/or high energy experiments. It is pointed out that such a mass splitting has a strong impact on the dark matter self-interaction strength. We derive the new parameter space of a pseudo-Dirac self-interacting dark matter. Interestingly, with increasing mass splitting, a weak scale dark matter mass window survives that could be probed by the LHC and future colliders.