Octant Degeneracy, Quadrant of leptonic CPV phase at Long Baseline Neutrino Experiments and Baryogenesis

TL;DR

This paper explores how baryogenesis can help resolve the degeneracy in determining the leptonic CP-violating phase and atmospheric mixing angle octant in long baseline neutrino experiments, providing predictions consistent with current data.

Contribution

It introduces a combined analysis of baryogenesis effects to resolve CPV phase and octant degeneracies at LBNEs, with updated predictions aligned with recent global neutrino data.

Findings

Favored δ_CP values around 1.3π-1.4π consistent with data

Baryogenesis enhances degeneracy resolution

Predictions constrained by latest BAU and global fit data

Abstract

In a recent work by 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 analysed 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 baryogenesis can enhance the effect of resolving this entanglement, and how possible values of the leptonic CP-violating phase $ \delta_{CP} $ can be predicted in this context. With respect to the latest global fit data of neutrino mixing angles, we predict the values of $ \delta_{CP} $ for different cases. In this context we present favoured values of $ \delta_{CP} $ ($ \delta_{CP} $ range at $ \geq $ 2$ \sigma $ ) constrained by the latest updated BAU range and also confront our predictions of $ \delta_{CP} $ with an up-to-date global analysis of neutrino oscillation data. We find that some region of the favoured $ \delta_{CP} $ parameter space lies within the best fit values around $ \delta_{CP} \simeq 1.3\pi-1.4 \pi $. A detailed analytic and numerical study of baryogenesis through leptogenesis is performed in this framework in a model independent way.