Parameter degeneracies and new plots in neutrino oscillations

Abstract

It is shown that plots of constant probabilities in the $(\sin^22\theta_{13}, 1/s^2_{23})$ plane enable us to see eightfold degeneracy easily. Using this plot, I discuss how an additional long baseline measurement resolves degeneracies after the JPARC experiment measures the oscillation probabilities $P(\nu_\mu\to\nu_e)$ and $P(\bar{\nu}_\mu\to\bar{\nu}_e)$ at $|\Delta m^2_{31}|L/4E=\pi/2$.