Hints for leptonic CP violation or New Physics?

TL;DR

This paper discusses how non-standard interactions could mimic signals of leptonic CP violation in neutrino experiments, emphasizing the need to distinguish new physics effects from genuine CP violation.

Contribution

It highlights that non-standard interactions with real couplings can produce signals similar to leptonic CP violation, complicating the interpretation of experimental results.

Findings

Non-standard interactions can mimic CP violation signals.

Current data shows a mild preference for large CP phase.

Distinguishing true CP violation from new physics requires robust testing.

Abstract

One of the major open questions in the neutrino sector is the issue of leptonic CP violation. Current global oscillation data shows a mild preference for a large, potentially maximal value for the Dirac CP phase in the neutrino mixing matrix. In this letter, we point out that New Physics in the form of neutral-current like non-standard interactions with real couplings would likely yield a similar conclusion even if CP in the neutrino sector were conserved. Therefore, the claim for a discovery of leptonic CP violation will require a robust ability to test New Physics scenarios.