Inelastic Dark Matter at the LHC Lifetime Frontier: ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA

TL;DR

This paper explores the potential of various LHC experiments to detect inelastic dark matter particles produced via dark photon decays, emphasizing the importance of high-energy collider searches for hidden sector particles in the 1-100 GeV mass range.

Contribution

It provides a comprehensive analysis of the capabilities of multiple LHC experiments to detect inelastic dark matter, including detailed calculations of scattering cross sections relevant for direct detection.

Findings

LHC experiments can produce GeV-scale dark matter from dark photon decays.

Detection prospects are promising for hidden sectors coupled through mediators >10 GeV.

Calculated dark matter-nucleon/electron scattering cross sections for experimental estimates.

Abstract

Visible signals from the decays of light long-lived hidden sector particles have been extensively searched for at beam dump, fixed-target, and collider experiments. If such hidden sectors couple to the Standard Model through mediators heavier than $\sim 10$ GeV, their production at low-energy accelerators is kinematically suppressed, leaving open significant pockets of viable parameter space. We investigate this scenario in models of inelastic dark matter, which give rise to visible signals at various existing and proposed LHC experiments, such as ATLAS, CMS, LHCb, CODEX-b, FASER, and MATHUSLA. These experiments can leverage the large center of mass energy of the LHC to produce GeV-scale dark matter from the decays of dark photons in the cosmologically motivated mass range of $\sim 1-100$ GeV. We also provide a detailed calculation of the radiative dark matter-nucleon/electron elastic scattering cross section, which is relevant for estimating rates at direct detection experiments.