Searching for MeV-scale Neutrinos with the DUNE Near Detector

TL;DR

This paper investigates the DUNE Near Detector's ability to detect MeV-scale right-handed neutrinos, demonstrating potential to significantly improve existing bounds through direct, model-independent searches.

Contribution

It introduces a novel sensitivity analysis of the DUNE Near Detector for MeV-scale neutrinos, focusing on decay product detection and background simulation.

Findings

Existing bounds can be improved by an order of magnitude.

The study demonstrates the detector's capability for model-independent searches.

Background analysis supports the feasibility of the proposed detection method.

Abstract

Adding right-handed neutrinos to the Standard Model is a natural and simple extension and is well motivated on both the theoretical and the experimental side. We extend the Standard Model by adding only one right-handed Majorana neutrino and study the sensitivity of the Near Detector of the DUNE experiment to the new physics parameters, namely the mixing parameters $|U_{e 4}|^2$ and $|U_{\mu 4}|^2$ and the mass $m_N$. The study relies on searches of the products of right-handed neutrino decays, which is possible thanks to an extremely intense beam and a state-of-the-art detection technology. This type of direct test is carried out with very few assumptions and in an almost-completely model-independent way, providing thus a strong result. A background analysis is also performed, simulating the detector performance to particle identification. It is found that the existing bounds in the MeV-range can be improved by one order of magnitude in different detection channels.