Learning about the CP phase in the next 10 years

Abstract

We assess the sensitivity to the lepton CP phase by accelerator and reactor experiments in the near future, characterizing it globally by means of the CP exclusion fraction measure. Such measure quantifies what fraction of the $\delta_{\rm CP}$ space can be excluded at given input values of $\theta_{23}$ and $\delta_{\rm CP}$. For some region of the parameter space, we find that T2K and NO$\nu$A combined can exclude about $30\%-40\%$ of the $\delta_{\rm CP}$ space at $3\sigma$ with a 5 years running in each neutrino and antineutrino modes. A determination of the mass hierarchy would be possible for a modest portion of the parameter space at $3\sigma$.