New look at the degeneracies in the neutrino oscillation parameters, and their resolution by T2K, NO$\nu$A and ICAL

Understand

At present the three major unknowns in neutrino oscillation parameters are the mass hierarchy, the octant of $\theta_{23}$ and the CP phase $\delta_{CP}$.

• It is well known that the presence of hierarchy$-\delta_{CP}$ and octant degeneracies affects the unambiguous determination of these parameters.
• In this paper we show that a comprehensive way to study the remaining parameter degeneracies is in the form of a generalized hierarchy-$\theta_{23}$ - $\delta_{CP}$ degeneracy.
• We show that the wrong-hierarchy and/or wrong-octant solutions can be further classified into eight different solutions depending on whether they occur with the wrong or right value of $\delta_{CP}$.