Octant Degeneracy, Quadrant of CPV phase at Long Baseline $\nu$ Experiments and Baryogenesis

TL;DR

This paper investigates how long baseline neutrino experiments can resolve the entanglement of CP violation phase and atmospheric mixing angle octant, predicting CPV phase values and relating them to baryogenesis and leptogenesis.

Contribution

It introduces a comprehensive analysis combining experimental data and leptogenesis to resolve CPV phase and octant degeneracies in neutrino oscillations.

Findings

Five CPV phase values are favored by baryon asymmetry constraints.

One predicted CPV phase value matches recent global fit results.

Leptogenesis enhances the ability to resolve phase and octant degeneracies.

Abstract

In a recent work by two of us, we have studied, how CP violation discovery potential can be improved at long baseline neutrino experiments (LBNE/DUNE), by combining with its ND (near detector) and reactor experiments. In this work, we discuss how this study can be further analyzed to resolve entanglement of the quadrant of leptonic CPV phase and Octant of atmospheric mixing angle $\theta_{23}$, at LBNEs. The study is done for both NH (Normal hierarchy) and IH (Inverted hierarchy), HO (Higher Octant) and LO (Lower Octant). We show how leptogenesis can enhance the effect of resolving this entanglement, and how possible values of the leptonic CPV phase can be predicted in this context. Carrying out numerical analysis based on the recent updated experimental results for neutrino mixing angles, we predict the values of the leptonic CPV phase for 152 possible cases. We also confront our predictions of the leptonic CPV phase with the updated global fit and find that five values of $\delta_{CP}$ are favoured by BAU constraints. One of the five values matches with the recent global fit value of $\delta_{CP}$ (leptonic CPV phase) close to 1.41 $\pi$ in our model independent scenario. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework in a model independent way.