Neutrino mixing and General Covariance in the inverse beta decay

TL;DR

This paper examines how neutrino mixing affects inverse beta decay in accelerated protons, demonstrating that consistent calculations across frames require flavor eigenstates, thus preserving General Covariance.

Contribution

It shows that using flavor eigenstates is essential for maintaining General Covariance in neutrino-related decay calculations, clarifying previous ambiguities.

Findings

Inertial and comoving frame calculations agree when using flavor states.

Neutrino mixing impacts the covariance of decay processes.

The results depend on the approximation of Pontecorvo states.

Abstract

We review recent developments on the role of neutrino mixing in the inverse beta decay of accelerated protons. We show that calculations in the inertial and comoving frames agree (thus preserving General Covariance) only when taking neutrino asymptotic states to be flavor (rather than mass) eigenstates. Our conclusions are valid in the approximation in which Pontecorvo states are correctly representing neutrino flavor states. We speculate about the general case involving exact flavor states and finally comment on other approaches recently appeared in literature.