New or $\nu$ Missing Energy? Discriminating Dark Matter from Neutrino Interactions at the LHC

TL;DR

This paper develops methods to distinguish dark matter signals from neutrino interactions at the LHC by analyzing missing energy distributions and setting new limits on neutrino interactions beyond the Standard Model.

Contribution

It introduces new constraints on non-standard neutrino interactions from LHC monojet data and proposes a way to infer dark matter mass and differentiate it from neutrino signals.

Findings

LHC monojet data sets stronger limits on NSIs than low-energy experiments for some flavors.

Shape analysis of missing energy can estimate dark matter mass above 1 TeV.

Multi-lepton searches provide stronger constraints on heavy mediators and help confirm or reject the dark matter hypothesis.

Abstract

Missing energy signals such as monojets are a possible signature of Dark Matter (DM) at colliders. However, neutrino interactions beyond the Standard Model may also produce missing energy signals. In order to conclude that new "missing particles" are observed the hypothesis of BSM neutrino interactions must be rejected. In this paper, we first derive new limits on these Non-Standard neutrino Interactions (NSIs) from LHC monojet data. For heavy NSI mediators, these limits are much stronger than those coming from traditional low-energy $\nu$ scattering or $\nu$ oscillation experiments for some flavor structures. Monojet data alone can be used to infer the mass of the "missing particle" from the shape of the missing energy distribution. In particular, 13 TeV LHC data will have sensitivity to DM masses greater than $\sim$ 1 TeV. In addition to the monojet channel, NSI can be probed in multi-lepton searches which we find to yield stronger limits at heavy mediator masses. The sensitivity offered by these multi-lepton channels provide a method to reject or confirm the DM hypothesis in missing energy searches.