Discovering New Light States at Neutrino Experiments

TL;DR

Neutrino experiments and related beam dump setups can be powerful tools for discovering weakly coupled light particles like pseudoscalars and vector bosons, surpassing previous constraints and offering new discovery opportunities.

Contribution

This paper demonstrates the enhanced sensitivity of existing and future neutrino experiments to weakly coupled light particles, expanding the search beyond previous laboratory and astrophysical constraints.

Findings

Neutrino experiments can detect long-lived pseudoscalars and vector bosons.

Future upgrades will improve discovery potential.

Muon beam experiments like COMPASS are effective for leptophilic PNGBs.

Abstract

Experiments designed to measure neutrino oscillations also provide major opportunities for discovering very weakly coupled states. In order to produce neutrinos, experiments such as LSND collide thousands of Coulombs of protons into fixed targets, while MINOS and MiniBooNE also focus and then dump beams of muons. The neutrino detectors beyond these beam dumps are therefore an excellent arena in which to look for long-lived pseudoscalars or for vector bosons that kinetically mix with the photon. We show that these experiments have significant sensitivity beyond previous beam dumps, and are able to partially close the gap between laboratory experiments and supernovae constraints on pseudoscalars. Future upgrades to the NuMI beamline and Project X will lead to even greater opportunities for discovery. We also discuss thin target experiments with muon beams, such as those available in COMPASS, and show that they constitute a powerful probe for leptophilic PNGBs.