Optimizing the $\theta_{23}$ octant search in long baseline neutrino   experiments
  We study the possibility of determining the octant of the neutrino mixing angle $\theta_{23}$, that is, whether $\theta_{23}> 45^\circ$ or $\theta_{23}<45^\circ$, in long baseline neutrino experiments. Here we numerically derived the sensitivity limits within which these experiments can determine, by measuring the probability of the $\nu_{\mu}\to \nu_{e}$ transitions, the octant of $\theta_{23}$ with a $5\sigma$ certainty. The interference of the CP violation angle $\delta$ with these limits, as well as the effects of the baseline length and the run-time ratio of neutrino and antineutrino modes of the beam have been analyzed. 
C.R. Das, Jukka Maalampi, Joao Pulido and Sampsa Vihonen
hep-ph