Mono-lepton Signature of a Neutrino-philic Dark Fermion at Hadron Colliders

TL;DR

This paper investigates mono-lepton signatures at the LHC to detect neutrino-philic dark fermions, demonstrating tensor operators' superior sensitivity and comparing collider constraints with direct detection experiments across a wide mass range.

Contribution

It provides a detailed EFT analysis of mono-lepton production, highlighting the LHC's ability to probe sub-GeV dark matter and comparing its sensitivity with direct detection experiments.

Findings

Tensor operators constrain energy scales up to 3 TeV.

LHC has an advantage in sub-GeV dark matter detection.

Direct detection experiments are effective in the 10-100 TeV range.

Abstract

Searching for dark matter at high-energy colliders and direct detection experiments can effectively cover nearly the entire mass range from the MeV to the TeV scale. In this paper, we focus on four-fermion contact interactions formulated within the framework of Effective Field Theory. Specifically, we present a detailed analysis of mono-lepton production at the LHC. Our results demonstrate that tensor operators exhibit superior sensitivity in the mono-lepton channel, constraining energy scales up to 3\,TeV for a nearly massless dark fermion using current LHC data. Moreover, these operators mediate both spin-independent and spin-dependent absorption processes in nuclear targets. A systematic comparison of constraints between direct detection experiments and collider measurements reveals the LHC's distinct advantage in exploring sub-GeV dark matter candidates while maintaining competitive sensitivity at the TeV scale. Notably, direct detection experiments such as Super-Kamiokande and Borexino achieve complementary constraints in the 10-100\,TeV mass range through their unique capabilities: utilization of light nuclei targets, large exposure volumes, and distinctive features of the recoil energy spectra.