Hint of CPT Violation in Short-Baseline Electron Neutrino Disappearance

TL;DR

This paper investigates potential CPT violation in neutrino oscillations by analyzing Gallium and reactor experiment data, finding a significant asymmetry in neutrino and antineutrino mixing angles.

Contribution

It provides the first evidence of a possible CPT-violating difference in neutrino and antineutrino mixing angles based on experimental data.

Findings

Evidence of a 3.5 sigma CPT-violating asymmetry in mixing angles.

No significant bounds on the squared-mass asymmetry.

Discrepancy between neutrino and antineutrino disappearance data.

Abstract

We analyzed the electron neutrino data of the Gallium radioactive source experiments and the electron antineutrino data of the reactor Bugey and Chooz experiments in terms of neutrino oscillations allowing for a CPT-violating difference of the squared-masses and mixings of neutrinos and antineutrinos. We found that the discrepancy between the disappearance of electron neutrinos indicated by the data of the Gallium radioactive source experiments and the limits on the disappearance of electron antineutrinos given by the data of reactor experiments reveal a positive CPT-violating asymmetry of the effective neutrino and antineutrino mixing angles (with a statistical significance of about 3.5 sigma), whereas the squared-mass asymmetry is practically not bounded.