Constraining the minimal dark matter fiveplet with LHC searches

TL;DR

This paper uses LHC search data to constrain a minimal dark matter model involving a fiveplet fermion, excluding masses up to 267 GeV and projecting future exclusions up to 520 GeV, with potential to distinguish signals from similar models.

Contribution

It provides the first collider constraints on a fermionic fiveplet dark matter candidate and discusses how to differentiate it from other models using LHC signatures.

Findings

Excluded fiveplet masses up to 267 GeV with current data

Projected exclusion reach up to 520 GeV with future data

Proposed methods to distinguish fiveplet signals from triplet models

Abstract

Adding a fermion to the standard model particle content which is a fiveplet under $SU(2)_L$ gives a dark matter candidate. The lightest state in the multiplet is neutral and automatically stable. The charged component of the multiplet is only slightly heavier and can travel a finite distance in the LHC detectors before decaying, leaving a charged track which disappears before the edge of the detector. We use the recent ATLAS and CMS searches to exclude a Majorana fiveplet with a mass up to 267 GeV. We estimate that with 3 ab$^{-1}$ of $\sqrt{s}=14$ TeV data this could be pushed to a mass 520 GeV. These exclusions are $\sim 10\%$ greater than what is achieved for wino-like dark matter. We also discuss how the doubly charged states could be used to distinguish a disappearing track signal from that given by a triplet such as the pure wino.