Probing the Neutrino Mass Hierarchy with Super-Kamiokande

TL;DR

This paper demonstrates that a superbeam directed at Super-Kamiokande can determine the neutrino mass hierarchy with high confidence within two years, leveraging matter effects in neutrino oscillations for large theta(13).

Contribution

It proposes a practical experimental setup to resolve the neutrino mass hierarchy using existing and planned superbeam facilities and Super-Kamiokande, focusing on matter effects in oscillations.

Findings

Mass hierarchy can be determined at 5 sigma in less than two years.

Large theta(13) enhances the sensitivity of the measurement.

Counting total appearance events suffices for hierarchy determination.

Abstract

We show that for recently discovered large values of theta(13), a superbeam with an average neutrino energy of ~ 5 GeV, such as those being proposed at CERN, if pointing to Super-Kamiokande (L = 8770 km), could reveal the neutrino mass hierarchy at 5 sigma in less than two years irrespective of the true hierarchy and CP phase. The measurement relies on the near resonant matter effect in the numu to nue oscillation channel, and can be done counting the total number of appearance events with just a neutrino beam.