Measuring the Dark Force at the LHC

TL;DR

This paper proposes a method to measure the properties of a hypothetical dark force mediator and dark matter particles at the LHC, which is crucial for understanding dark matter relic density.

Contribution

It introduces a novel approach to determine the dark force coupling, mediator mass, and DM mass simultaneously using collider data.

Findings

The dark force coupling can be precisely measured at the LHC.

The mediator's mass is obtained from lepton jet decays.

The DM particle mass is determined using the MT2 technique.

Abstract

A long-range ``dark force'' has recently been proposed to mediate the dark matter (DM) annihilation. If DM particles are copiously produced at the Large Hadron Collider (LHC), the light dark force mediator will also be produced through radiation. We demonstrate how and how precise we can utilize this fact to measure the coupling constant of the dark force. The light mediator's mass is measured from the ``lepton jet'' it decays to. In addition, the mass of the DM particle is determined using the MT2 technique. Knowing these quantities is critical for calculating the DM relic density.