Determination of the $\theta_{23}$ octant in LBNO

TL;DR

This paper evaluates LBNO's potential to determine whether the neutrino mixing angle θ23 is in the lower or higher octant, addressing a key ambiguity in neutrino oscillation parameters.

Contribution

It analyzes LBNO's capability to resolve the θ23 octant degeneracy, which is crucial for understanding neutrino mixing.

Findings

LBNO can effectively distinguish between LO and HO solutions.

The experiment's sensitivity depends on the true value of θ23.

Results support LBNO's potential to clarify neutrino mixing parameters.

Abstract

According to the recent results of the neutrino oscillation experiment MINOS, the neutrino mixing angle $\theta_{23}$ may not be maximal ($45^{\circ}$). Two nearly degenerate solutions are possible, one in the lower octant (LO) where $\theta_{23}<45^{\circ}$, and one in the higher octant (HO) where $\theta_{23}>45^{\circ}$. Long baseline experiments measuring the $\nu_{\mu}\rightarrow\nu_{e}$ are capable of resolving this degeneracy. In this work we study the potential of the planned European LBNO experiment to distinguish between the LO and HO solutions.