Distinguishing Beyond-Standard Model Effects in Neutrino Oscillation

TL;DR

This paper evaluates DUNE's capability to differentiate various beyond-standard neutrino oscillation models, such as decay, non-standard interactions, decoherence, and equivalence principle violation, and examines their impact on CP-violation measurements.

Contribution

It systematically compares the distinguishability of multiple beyond-standard neutrino hypotheses and analyzes their effects on CP-violation phase measurements.

Findings

Quantum decoherence and equivalence principle violation are easiest to distinguish.

Some models are statistically indistinguishable but cause significant CP phase deviations.

The analysis highlights potential challenges in identifying new physics in neutrino experiments.

Abstract

We systematically assess the DUNE experiment's ability to distinguish between various beyond-standard neutrino oscillation hypotheses pair combinations. For a pair comparison, we evaluate the statistical separation, where one hypothesis plays the role of the true signal while the other corresponds to the test signal. The beyond-standard neutrino oscillation hypotheses under scrutiny include neutrino decay (invisible and visible), non-standard interactions, quantum decoherence, and the violation of the equivalence principle. When taken as the true model, we found that either quantum decoherence or the violation of the equivalence principle are the easiest to differentiate compared to the rest of the hypotheses. Additionally, from our statistical test, we investigate potential discrepancies between the measured CP-violation phase $\delta_{CP}$ relative to its true value, which could occur for a given comparison. In our analysis, we will take the true values of $\delta_{CP}$ as $-90^\circ$ and $180^\circ$. Notably, even in cases where the beyond-standard neutrino oscillation hypotheses scenarios are statistically indistinguishable, the measured value can exhibit significant deviations from its true value.