Looking for new charged states at the LHC: Signatures of Magnetic and Rayleigh Dark Matter

TL;DR

This paper explores potential new charged particles at the LHC arising from magnetic and Rayleigh dark matter models, proposing targeted searches to detect these states and discussing current constraints and future challenges.

Contribution

It categorizes electroweak-charged states predicted by dark matter models and proposes optimized LHC search strategies to discover or constrain them.

Findings

Models with SU(2)-singlet states remain viable.

Targeted multi-tau searches outperform existing methods.

Some tau-dominated scenarios are undetectable at current LHC luminosities.

Abstract

Magnetic and Rayleigh dark matter are models describing weak interactions of dark matter with electromagnetism through non-renormalizable operators of dimensions 5 and 7, respectively. Such operators motivate the existence of heavier states that couple to dark matter and are also charged under the electroweak interactions. The recent hints of a gamma-ray line in the Fermi data suggest that these states may be light enough to be produced at the LHC. We categorize such states according to their charges and decay modes, and we examine the corresponding LHC phenomenology. We emphasize unconstrained models that can be discovered in targeted searches at the upgraded LHC run, while also enumerating models excluded by current data. Generally, models with SU(2)-singlet states or models where the charged states decay predominantly to tau leptons and/or gauge bosons are still viable. We propose searches to constrain such models and, in particular, find superior performance over existing proposals for multi-tau analyses. Finally, we note several scenarios, especially those dominated by tau final states, that cannot be probed even with 300/fb at LHC14, motivating the further refinement of tau lepton searches to improve sensitivity to such final states.