Testing GeV-Scale Dark Matter with Fixed-Target Missing Momentum Experiments

TL;DR

This paper proposes a fixed-target missing momentum experiment to detect sub-GeV dark matter and dark photons, significantly improving sensitivity and covering most of the viable parameter space for thermal or asymmetric dark matter models.

Contribution

It introduces a novel experimental approach using missing energy-momentum measurements to detect light dark matter and dark photons, surpassing current constraints by several orders of magnitude.

Findings

Can improve constraints by 2-6 orders of magnitude

Reaches sensitivity as low as ε² ~ 10⁻¹⁴

Explores nearly all viable parameter space for relevant dark matter models

Abstract

We describe an approach to detect dark matter and other invisible particles with mass below a GeV, exploiting missing energy-momentum measurements and other kinematic features of fixed-target production. In the case of an invisibly decaying MeV-GeV-scale dark photon, this approach can improve on present constraints by 2-6 orders of magnitude over the entire mass range, reaching sensitivity as low as $\epsilon^2\sim 10^{-14}$. Moreover, the approach can explore essentially all of the viable parameter space for thermal or asymmetric dark matter annihilating through the vector portal.