Dark Matter Searches with a Mono-Z' jet

TL;DR

This paper proposes a novel collider search strategy for dark matter involving a mono-Z' jet signature, which can significantly improve bounds on dark matter interactions compared to traditional mono-jet searches.

Contribution

It introduces a new mono-Z' jet signature from dark matter models with a GeV-scale Z', and demonstrates its potential to enhance detection sensitivity at colliders.

Findings

Mono-Z' jet signature can be distinguished from QCD jets with high significance.

Searches for mono-Z' jets can improve bounds on dark matter-nucleon cross sections by over an order of magnitude.

Jet-substructure analysis is effective in identifying Z' jets in collider data.

Abstract

We study collider signatures of a class of dark matter models with a GeV-scale dark Z'. At hadron colliders, the production of dark matter particles naturally leads to associated production of the Z', which can appear as a narrow jet after it decays hadronically. Contrary to the usual mono-jet signal from initial state radiation, the final state radiation of dark matter can generate the signature of a mono-Z' jet plus missing transverse energy. Performing a jet-substructure analysis to tag the Z' jet, we show that these Z' jets can be distinguished from QCD jets at high significance. Compared to mono-jets, a dedicated search for mono-Z' jet events can lead to over an order of magnitude stronger bounds on the interpreted dark matter-nucleon scattering cross sections.