Heavy Neutrino searches through Double-Bang Events at Super-Kamiokande, DUNE, and Hyper-Kamiokande

TL;DR

This paper investigates the potential to detect heavy neutrinos through distinctive double-bang events at Super-Kamiokande, DUNE, and Hyper-Kamiokande, providing current constraints and future sensitivity projections for these experiments.

Contribution

It introduces the concept of using double-bang events to search for heavy neutrinos and evaluates current and future experimental sensitivities.

Findings

Current Super-Kamiokande data may already constrain heavy neutrino models.

Projected sensitivities at DUNE and Hyper-Kamiokande are promising for future searches.

Double-bang events offer a low-background signature for heavy neutrino detection.

Abstract

A variety of new physics scenarios allow for neutrinos to up-scatter into a heavy neutral lepton state. For a range of couplings and neutrino energies, the heavy neutrino may travel some distance before decaying to visible final states. When both the up-scattering and decay occur within the detector volume, these "double bang" events produce distinctive phenomenology with very low background. In this work, we first consider the current sensitivity at Super-Kamiokande via the atmospheric neutrino flux, and find current data may already provide new constraints. We then examine projected future sensitivity at DUNE and Hyper-Kamiokande, including both atmospheric and beam flux contributions to double-bang signals.