Dark Tridents at Off-Axis Liquid Argon Neutrino Detectors

TL;DR

This paper introduces dark tridents as a novel detection channel for dark sector particles in neutrino experiments, demonstrating their potential to explore new physics with current and future liquid argon detectors at Fermilab.

Contribution

It proposes the concept of dark tridents, models their production and decay in neutrino detectors, and evaluates their detectability in existing and upcoming experiments.

Findings

MicroBooNE has enough data to test the model.

Future experiments can probe new parameter space.

Dark tridents provide a clean signature for dark sector searches.

Abstract

We present dark tridents, a new channel for exploring dark sectors in short-baseline neutrino experiments. Dark tridents are clean, distinct events where, like neutrino tridents, the scattering of a very weakly coupled particle leads to the production of a lepton--antilepton pair. Dark trident production occurs in models where long-lived dark-sector particles are produced along with the neutrinos in a beam-dump environment and interact with neutrino detectors downstream, producing an on-shell boson which decays into a pair of charged leptons. We focus on a simple model where the dark matter particle interacts with the standard model exclusively through a dark photon, and concentrate on the region of parameter space where the dark photon mass is smaller than twice that of the dark matter particle and hence decays exclusively into standard-model particles. We compute event rates and discuss search strategies for dark tridents from dark matter at the current and upcoming liquid argon detectors aligned with the Booster beam at Fermilab -- MicroBooNE, SBND, and ICARUS -- assuming the dark sector particles are produced off-axis in the higher energy NuMI beam. We find that MicroBooNE has already recorded enough data to be competitive with existing bounds on this dark sector model, and that new regions of parameter space will be probed with future data and experiments.