Timing and Multi-Channel: Novel Method for Determining the Neutrino Mass Ordering from Supernovae

TL;DR

This paper introduces a new method to determine neutrino mass ordering by analyzing the timing of early supernova neutrino signals across multiple detectors, enabling mass hierarchy identification with minimal events.

Contribution

The paper proposes a novel timing-based approach for neutrino mass ordering determination that does not require high statistics and can be integrated into supernova early warning systems.

Findings

Mass ordering can be determined at ~2 sigma CL with early supernova neutrino timing.

Approximately 10 events are sufficient for mass hierarchy discovery.

The method enhances supernova localization through timing and mass ordering interplay.

Abstract

One of the few remaining unknowns in the standard three-flavor neutrino oscillation paradigm is the ordering of neutrino masses. In this work we propose a novel method for determining neutrino mass ordering using the time information on early supernova neutrino events. In a core-collapse supernova, neutrinos are produced earlier than antineutrinos and, depending on the mass ordering which affects the adiabatic flavor evolution, may cause earlier observable signals in $\nu_e$ detection channels than in others. Hence, the time differences are sensitive to the mass ordering. We find that using the time information on the detection of the first galactic supernova events at future detectors like DUNE, JUNO and Hyper-Kamiokande, the mass ordering can already be determined at $\sim 2 \sigma$ CL, while $\mathcal{O}(10)$ events suffice for the discovery. Our method does not require high statistics and could be used within the supernova early warning system (SNEWS) which will have access to the time information on early supernova neutrino events recorded in a number of detectors. The method proposed in this paper also implies a crucial interplay between the mass ordering and the triangulation method for locating supernovae.