Rephasing invariance and the neutrino mu-tau symmetry

TL;DR

This paper explores the mu-tau symmetry in neutrino mixing, demonstrating its invariance in matter and simplifying transition probabilities, with implications for long baseline neutrino experiments.

Contribution

It introduces a rephasing invariant parametrization that preserves mu-tau symmetry in matter, simplifying the analysis of neutrino oscillations.

Findings

Mu-tau symmetry remains approximately valid in matter.

Transition probabilities are simplified using the invariant parametrization.

Applications to long baseline experiments are discussed.

Abstract

The vacuum neutrino mixing is known to exhibit an approximate $\mu-\tau$ symmetry, which was shown to be preserved for neutrino propagating in matter. This symmetry reduces the neutrino transition probabilities to very simple forms when expressed in a rephasing invariant parametrization introduced earlier. Applications to long baseline experiments are discussed.