The impact of heavy-quark loops on LHC dark matter searches

TL;DR

This paper demonstrates that including heavy-quark loop effects in LHC dark matter search analyses significantly strengthens the constraints on dark matter interactions mediated by heavy scalars or pseudoscalars.

Contribution

The study calculates the impact of heavy-quark loops on LHC monojet search constraints, revealing a substantial enhancement in the predicted cross sections and bounds.

Findings

Heavy-quark loops increase predicted cross sections.

Inclusion of loops improves LHC constraints.

Significant tightening of dark matter-proton scattering bounds.

Abstract

If only tree-level processes are included in the analysis, LHC monojet searches give weak constraints on the dark matter-proton scattering cross section arising from the exchange of a new heavy scalar or pseudoscalar mediator with Yukawa-like couplings to quarks. In this letter we calculate the constraints on these interactions from the CMS 5.0/fb and ATLAS 4.7/fb searches for jets with missing energy including the effects of heavy-quark loops. We find that the inclusion of such contributions leads to a dramatic increase in the predicted cross section and therefore a significant improvement of the bounds from LHC searches.