Towards First Detection of the Solar MSW Transition With JUNO

TL;DR

This paper proposes a new technique enabling JUNO to detect the MSW neutrino flavor transition from the Sun with high significance, which would confirm a key prediction of neutrino physics.

Contribution

The authors introduce a novel background suppression method that allows JUNO to observe the solar MSW transition with over 4σ significance within a decade.

Findings

New background suppression technique demonstrated.

JUNO can detect the MSW transition at >4σ significance.

Supports the neutrino mixing framework.

Abstract

Matter-induced neutrino flavor mixing (the Mikheyev-Smirnov-Wolfenstein, or MSW, effect) is a central prediction of the neutrino mixing framework, but it has not been conclusively observed. Direct observation of the energy-dependent MSW transition in the solar electron-neutrino survival probability would solve this, but backgrounds have been prohibitive. We show that our new technique for suppressing muon-induced spallation backgrounds will allow JUNO to measure the MSW transition at $>$4$\sigma$ significance in 10 years. This would strongly support upcoming multi-\$1B next-generation long-baseline experiments and their goals in cementing the neutrino mixing framework.