Searches for Decays of New Particles in the DUNE Multi-Purpose Near Detector

TL;DR

This paper investigates the potential of the DUNE Multi-Purpose Detector to discover or constrain new physics particles, such as dark vectors and heavy neutral leptons, by analyzing their decay signatures with enhanced sensitivity.

Contribution

It introduces the use of the DUNE MPD for new physics searches, highlighting its superior sensitivity to semi-long-lived particles compared to liquid argon detectors.

Findings

MPD can extend existing bounds on dark vector bosons.

MPD's momentum and charge measurements improve detection sensitivity.

The study demonstrates MPD's potential in various new physics scenarios.

Abstract

One proposed component of the upcoming Deep Underground Neutrino Experiment (DUNE) near detector complex is a multi-purpose, magnetized, gaseous argon time projection chamber: the Multi-Purpose Detector (MPD). We explore the new-physics potential of the MPD, focusing on scenarios in which the MPD is significantly more sensitive to new physics than a liquid argon detector, specifically searches for semi-long-lived particles that are produced in/near the beam target and decay in the MPD. The specific physics possibilities studied are searches for dark vector bosons mixing kinetically with the Standard Model hypercharge group, leptophilic vector bosons, dark scalars mixing with the Standard Model Higgs boson, and heavy neutral leptons that mix with the Standard Model neutrinos. We demonstrate that the MPD can extend existing bounds in most of these scenarios. We illustrate how the ability of the MPD to measure the momentum and charge of the final state particles leads to these bounds.