Parameter degeneracy and hierarchy sensitivity of NO$\nu$A in presence of sterile neutrino

TL;DR

This paper investigates how the presence of a light sterile neutrino affects the neutrino mass hierarchy determination in the NO$ u$A experiment, revealing new degeneracies that could alter the expected hierarchy sensitivity.

Contribution

It introduces the impact of an eV-scale sterile neutrino on hierarchy sensitivity and identifies new degeneracies absent in the standard three-flavor model.

Findings

Sterile neutrino introduces new degeneracies affecting hierarchy measurement.

Standard hierarchy sensitivity can be compromised by sterile neutrino effects.

Implications for future neutrino experiments' analysis strategies.

Abstract

The first hint of neutrino mass hierarchy is expected to come from the NO$\nu$A experiment in Fermilab as the present best-fit parameter space i.e., normal hierarchy and $\delta_{CP}=-90^\circ$ is the favourable parameter space for NO$\nu$A where there is no degeneracy. But this situation may change if the standard three flavour framework is not complete and there is existence of new physics. In this work we consider the presence of an extra light sterile neutrino at the eV scale and study the new degeneracies which are absent in the standard three flavour framework. We also study the effect of these new degeneracies on the hierarchy measurement of NO$\nu$A.