Neutrino mass hierarchy determination at reactor antineutrino experiments

TL;DR

This paper discusses the design, simulation, and expected capabilities of the JUNO and RENO-50 reactor antineutrino experiments to determine the neutrino mass hierarchy within the next decade, leveraging advanced detector technology.

Contribution

It presents the detailed design and simulation results of JUNO and RENO-50, highlighting their potential to resolve the neutrino mass hierarchy without matter effect analysis.

Findings

JUNO's energy resolution enables 3-4 sigma sensitivity.

JUNO and RENO-50 are likely to determine the hierarchy within 10 years.

Optimized site location enhances sensitivity for hierarchy determination.

Abstract

After the neutrino mixing angle $\theta_{13}$ has been precisely measured by the reactor antineutrino experiments, one of the most important open questions left in neutrino physics is the neutrino mass hierarchy. Jiangmen Underground Neutrino Observatory (JUNO) is designed to determine the neutrino mass hierarchy (MH) without exploring the matter effect. The JUNO site location is optimized to have the best sensitivity for the mass hierarchy determination. JUNO will employ a 20 kton liquid scintillator detector located in a laboratory 700 meters underground. The excellent energy resolution and PMT coverage will give us an unprecedented opportunity to reach a 3-4 $\sigma$ precision. In this paper, the JUNO detector design and simulation work will be presented. Also, RENO-50, another medium distance reactor antineutrino experiment, will do a similar measurement. With the efforts of these experiments, it is very likely that the neutrino mass hierarchy will be determined in the next 10 years.