Determining neutrino mass hierarchy from electron disappearance at a Low energy neutrino factory

TL;DR

This paper investigates how a low energy neutrino factory can determine the neutrino mass hierarchy using electron neutrino disappearance channels, achieving high confidence in just two years of data collection.

Contribution

It demonstrates that LENF can determine the neutrino mass hierarchy independently of delta_{CP} and theta_{23} octant uncertainties using electron neutrino disappearance channels.

Findings

Possible to exclude the wrong hierarchy at 5 sigma in 2 years

Electron neutrino disappearance channels are effective for hierarchy determination

Method is robust against unknown CP phase and theta_{23} octant

Abstract

Recent measurements of large theta_{13} by Daya Bay and RENO reactor experiments have opened up the possibility of determining the neutrino mass hierarchy, i.e. the sign of the mass squared splitting Delta m_{31}^2, the CP-violating phase delta_{CP} and the octant of theta_{23}. In the light of this result, we study the performance of a low energy neutrino factory (LENF) for determination of the mass hierarchy. In particular, we explore the potential of the nu_e$ and bar{\nu}_e disappearance channels at LENF to determine the neutrino mass hierarchy, that is free from the uncertainties arising from the unknown delta_{CP} phase and the theta_{23} octant. We find that using these electron neutrino (antineutrino) disappearance channels with a standard LENF, it is possible to exclude the wrong hierarchy at 5 sigma with only 2 years of running.