Effect of sterile phases on degeneracy resolution capabilities of LBL experiments

TL;DR

This paper investigates how sterile neutrino phases influence the ability of long-baseline experiments to resolve parameter degeneracies, highlighting the importance of phase differences over individual phase variations.

Contribution

It demonstrates that the difference between sterile phases significantly impacts degeneracy resolution, providing insights into optimizing experimental sensitivity.

Findings

Sterile phases are always coupled in oscillation probabilities.

Phase difference has a greater effect on event rates than individual phase variations.

Identifies the sterile phase difference that minimally affects degeneracy resolution.

Abstract

In sterile neutrino (3+1) parameterisation, we observe that sterile phases ($\delta_{14},\delta_{24}$) are always together in oscillation probability, even when the MSW effect is considered. We see that the difference between the sterile phases has a more dominating effect over event rates compared to small variations due to changes in individual values. In this work, we show the value of sterile phase difference ($\delta_{14}-\delta_{24}$) that least affects the parameter degeneracy resolution of $\delta_{13},\theta_{23}$ at long-baseline experiments.