T violation without complex entries in lepton mixing matrix

TL;DR

This paper shows that T violation in neutrino oscillations can occur even with a real lepton mixing matrix, providing conditions and probabilities for such violations in matter and electromagnetic fields.

Contribution

It introduces a novel mechanism for T violation without complex entries in the lepton mixing matrix and derives related transition probabilities.

Findings

T violation can occur with a real lepton mixing matrix.

Derived T-violating spin-flavor transition probabilities.

Transition probabilities differ for neutrinos and antineutrinos in electromagnetic fields.

Abstract

We demonstrate that T invariance can be violated even when Pontecorvo--Maki--Nakagawa--Sakata lepton mixing matrix is real. We obtain a sufficient condition of T violation in neutrino oscillations in matter and electromagnetic field. In the two-flavor model we derive the T-violating spin-flavor transition probabilities. Then we prove that the transition probabilities for neutrino in moving medium in electromagnetic field differ from those for antineutrino in matter composed of antiparticles and electromagnetic field only in the sign of the T-violating term.