False Signals of CP-Invariance Violation at DUNE

TL;DR

This paper demonstrates that certain CP-invariant new physics scenarios can mimic CP-violation signals in DUNE, complicating the interpretation of potential discoveries of CP violation.

Contribution

It identifies specific CP-invariant models that are indistinguishable from CP-violating scenarios in DUNE data, highlighting potential ambiguities in interpreting results.

Findings

CP-invariant new physics can mimic CP violation signals in DUNE

Examples include non-standard neutrino interactions and a fourth neutrino state

Combining DUNE data with other experiments can help resolve ambiguities

Abstract

One of the main goals of the Deep Underground Neutrino Experiment (DUNE) is to look for new sources of CP-invariance violation. Another is to significantly test the three-massive-neutrinos paradigm. Here, we show that there are CP-invariant new physics scenarios which, as far as DUNE data are concerned, cannot be distinguished from the three-massive-neutrinos paradigm with very large CP-invariance violating effects. We discuss examples with non-standard neutrino interactions and with a fourth neutrino mass eigenstate. We briefly discuss how ambiguities can be resolved by combining DUNE data with data from other long-baseline experiments, including Hyper-Kamiokande.