Discriminating sterile neutrinos and unitarity violation with CP invariants

TL;DR

This paper introduces a new method using CP invariants to distinguish sterile neutrinos and unitarity violation in neutrino oscillations, enabling model discrimination with minimal measurements.

Contribution

It proposes a parametrization-independent approach using CP amplitudes to analyze neutrino oscillation data for new physics beyond the Standard Model.

Findings

CP amplitudes can differentiate models with sterile neutrinos and unitarity violation.

Correlations among amplitudes allow model rejection with only three measurements.

The method provides a way to test new physics in upcoming neutrino experiments.

Abstract

We present a new method to analyze upcoming results in the search for CP violating neutrino oscillations. The CP violating amplitudes $\mathcal{A}_{\alpha\beta}^{kj}$ provide parametrization independent observables, which will be accessible by experiments soon. The strong prediction of a unique $\mathcal{A}_{\alpha\beta}^{kj}$ (the Jarlskog invariant) in case of the standard three neutrino model does not hold in models with new physics beyond the Standard Model. Nevertheless there are still correlations among the amplitudes depending on the specific model. Due to these correlations it is possible to reject specific new physics models by determining only 3 of the CP violating amplitudes.