Optimizing the $\theta_{23}$ octant search in long baseline neutrino experiments

TL;DR

This paper investigates how long baseline neutrino experiments can determine whether the mixing angle θ23 is greater or less than 45°, analyzing sensitivities, the impact of CP violation, baseline length, and beam mode ratios.

Contribution

The study provides numerical sensitivity limits for octant determination in neutrino experiments, considering CP interference, baseline effects, and beam mode ratios.

Findings

Sensitivity limits for 5σ octant determination derived

CP violation angle δ affects octant sensitivity

Baseline length and neutrino/antineutrino run ratios influence results

Abstract

We study the possibility of determining the octant of the neutrino mixing angle $\theta_{23}$, that is, whether $\theta_{23}> 45^\circ$ or $\theta_{23}<45^\circ$, in long baseline neutrino experiments. Here we numerically derived the sensitivity limits within which these experiments can determine, by measuring the probability of the $\nu_{\mu}\to \nu_{e}$ transitions, the octant of $\theta_{23}$ with a $5\sigma$ certainty. The interference of the CP violation angle $\delta$ with these limits, as well as the effects of the baseline length and the run-time ratio of neutrino and antineutrino modes of the beam have been analyzed.