The use of a high intensity neutrino beam from the ESS proton linac for measurement of neutrino CP violation and mass hierarchy

TL;DR

This paper proposes using a high-intensity neutrino beam from the ESS proton linac combined with a large underground detector to measure neutrino CP violation and determine the mass hierarchy, showing promising sensitivity within certain baselines.

Contribution

It introduces a novel experimental setup combining ESS proton linac with a megaton water Cherenkov detector for neutrino physics, providing preliminary sensitivity estimates.

Findings

CP violation could be discovered at 5σ confidence in 48% of the parameter space.

Neutrino mass hierarchy could be determined at 3σ confidence over most of the parameter space.

Optimal baseline distance is around 400 km for maximum sensitivity.

Abstract

It is proposed to complement the ESS proton linac with equipment that would enable the production, concurrently with the production of the planned ESS beam used for neutron production, of a 5 MW beam of 10$^{23}$ 2.5 GeV protons per year in microsecond short pulses to produce a neutrino Super Beam, and to install a megaton underground water Cherenkov detector in a mine to detect $\nu_e$ appearance in the produced $\nu_\mu$ beam. Results are presented of preliminary calculations of the sensitivity to neutrino CP violation and the mass hierarchy as a function of the neutrino baseline. The results indicate that, with 8 years of data taking with an antineutrino beam and 2 years with a neutrino beam and a baseline distance of around 400 km, CP violation could be discovered at 5 $\sigma$ (3 $\sigma$) confidence level in 48% (73%) of the total CP violation angular range. With the same baseline, the neutrino mass hierarchy could be determined at 3 $\sigma$ level over most of the total CP violation angular range. There are several underground mines with a depth of more than 1000 m, which could be used for the creation of the underground site for the neutrino detector and which are situated within or near the optimal baseline range.