Dark Matter Signals in Dilepton Production at Hadron Colliders

TL;DR

This paper investigates how dark matter interactions can produce distinctive features in dilepton invariant mass spectra at hadron colliders, offering new ways to detect or constrain dark matter models through radiative effects.

Contribution

It introduces the concept of 'monocline' features in dilepton spectra caused by dark matter with scalar mediators and analyzes their potential as signals at current and future colliders.

Findings

Monocline features start at roughly twice the dark matter mass.

Regions of parameter space exist where the absence of monoclines constrains models.

High luminosity 14 TeV LHC and 100 TeV collider sensitivities are evaluated.

Abstract

We show that new physics can show up in dileptonic events through its radiative contributions to the dilepton invariant mass, leading to unique "monocline" features in $m_{\ell\ell}$, as well as the angular distribution of the leptons. We focus in particular on the case of dark matter with scalar messengers coupling it to the quarks and leptons. Consistent thermal models require the dark matter to have masses of 100's GeV and have $\gsim 1$ couplings to the Standard Model (SM), implying that radiative corrections to the SM Drell-Yan rate can be sizeable. We consider the case of Majorana, Dirac, and pseudo-Dirac dark matter and show that there are regions of parameter space where the non-existence of a monocline, which starts at roughly twice the dark matter mass, $m_{\ell\ell} \sim 2 m_\chi$, places the strongest constraint on the model. We make predictions for the sensitivities at the high luminosity 14 TeV LHC as well as a future 100 TeV proton-proton collider. We find that our dilepton signal is most sensitive when the mediator and the dark matter are nearly degenerate and conventional MET-based searches are least sensitive.