Simplified DM models with the full SM gauge symmetry: the case of t-channel colored scalar mediators

Abstract

The general strategy for dark matter (DM) searches at colliders currently relies on simpli fi ed models. In this paper, we propose a new t -channel UV-complete simpli fi ed model that improves the existing simpli fi ed DM models in two important respects: (i) we impose the full SM gauge symmetry including the fact that the left-handed and the righthanded fermions have two independent mediators with two independent couplings, and (ii) we include the renormalization group evolution when we derive the e ff ective Lagrangian for DM-nucleon scattering from the underlying UV complete models by integrating out the t -channel mediators. The fi rst improvement will introduce a few more new parameters compared with the existing simpli fi ed DM models. In this study we look at the e ff ect this broader set of free parameters has on direct detection and the mono-X + MET (X = jet, W; Z) signatures at 13TeV LHC while maintaining gauge invariance of the simplifi ed model under the full SM gauge group. We fi nd that the direct detection constraints require DM masses less than 10 GeV in order to produce phenomenologically interesting collider signatures. Additionally, for a fi xed mono-W cross section it is possible to see very large di ff erences in the mono-jet cross section when the usual simpli fi ed model assumptions are loosened and isospin violation between RH and LH DM-SM quark couplings are allowed (c) The Authors. Article funded by SCOAP3.