Mono-W Dark Matter Signals at the LHC: Simplified Model Analysis

TL;DR

This paper investigates mono-W signals of dark matter at the LHC within gauge invariant simplified models, finding that such signals are less constraining than mono-jet searches and challenging to observe at 14 TeV.

Contribution

It introduces gauge invariant simplified models for mono-W dark matter signals and assesses their LHC reach, highlighting the reduced impact of isospin violation in these models.

Findings

Mono-W signals are less constraining than mono-jet searches.

Isospin violating effects are small in gauge invariant models.

Mono-W signals are challenging to detect at 14 TeV with high luminosity.

Abstract

We study mono-W signals of dark matter (DM) production at the LHC, in the context of gauge invariant renormalizable models. We analyze two simplified models, one involving an s-channel Z' mediator and the other a t-channel colored scalar mediator, and consider examples in which the DM-quark couplings are either isospin conserving or isospin violating after electroweak symmetry breaking. While previous work on mono-W signals have focused on isospin violating EFTs, obtaining very strong limits, we find that isospin violating effects are small once such physics is embedded into a gauge invariant simplified model. We thus find that the 8 TeV mono-W results are much less constraining than those arising from mono-jet searches. Considering both the leptonic (mono-lepton) and hadronic (mono fat jet) decays of the W, we determine the 14 TeV LHC reach of the mono-W searches with 3000 fb$^{-1}$ of data. While a mono-W signal would provide an important complement to a mono-jet discovery channel, existing constraints on these models imply it will be a challenging signal to observe at the 14 TeV LHC.