Probing the neutrino mass ordering with KM3NeT-ORCA: Analysis and perspectives

TL;DR

This paper evaluates the potential of the KM3NeT-ORCA detector to determine the neutrino mass ordering by analyzing atmospheric neutrino data, emphasizing the importance of controlling systematic uncertainties and improving event reconstruction.

Contribution

It provides a detailed analysis of systematic uncertainties affecting ORCA's sensitivity to neutrino mass ordering and discusses strategies to enhance detection capabilities.

Findings

Spectral shape uncertainties must be controlled at the percent level.

Better priors on the theta-23 mixing angle improve sensitivity.

Enhanced flavor identification increases the likelihood of correctly determining the mass ordering.

Abstract

The discrimination of the two possible options for the neutrino mass ordering (normal or inverted) is a major goal for current and future neutrino oscillation experiments. Such goal might be reached by observing high-statistics energy-angle spectra of events induced by atmospheric neutrinos and antineutrinos propagating in the Earth matter. Large volume water-Cherenkov detectors envisaged to this purpose include the so-called KM3NeT-ORCA project (in seawater) and the IceCube-PINGU project (in ice). Building upon a previous work focused on PINGU, we study in detail the effects of various systematic uncertainties on the ORCA sensitivity to the mass ordering, for the reference configuration with 9 m vertical spacing. We point out the need to control spectral shape uncertainties at the percent level, the effects of better priors on the theta-23 mixing parameter, and the benefits of an improved flavor identification in reconstructed ORCA events.