Higher-order QCD predictions for dark matter production at the LHC in simplified models with s-channel mediators

TL;DR

This paper provides advanced QCD predictions for dark matter production at the LHC using simplified models with s-channel mediators, highlighting the importance of higher-order corrections for accurate cross sections and distribution shapes.

Contribution

It implements s-channel mediator models in MadGraph5_aMC@NLO, enabling systematic inclusion of higher-order QCD corrections for dark matter production predictions.

Findings

Higher-order QCD corrections significantly affect production rates and distribution shapes.

Next-to-leading order effects reduce theoretical uncertainties.

Predictions include dark matter with jets and top-quark pairs at the LHC.

Abstract

Weakly interacting dark matter particles can be pair-produced at colliders and detected through signatures featuring missing energy in association with either QCD/EW radiation or heavy quarks. In order to constrain the mass and the couplings to standard model particles, accurate and precise predictions for production cross sections and distributions are of prime importance. In this work, we consider various simplified models with s-channel mediators. We implement such models in the FeynRules/MadGraph5_aMC@NLO framework, which allows to include higher-order QCD corrections in realistic simulations and to study their effect systematically. As a first phenomenological application, we present predictions for dark matter production in association with jets and with a top-quark pair at the LHC, at next-to-leading order accuracy in QCD, including matching/merging to parton showers. Our study shows that higher-order QCD corrections to dark matter production via s-channel mediators have a significant impact not only on total production rates, but also on shapes of distributions. We also show that the inclusion of next-to-leading order effects results in a sizeable reduction of the theoretical uncertainties.