Status of three-neutrino oscillation parameters, circa 2013

The standard three-neutrino (3ν) oscillation framework is being increasingly refined by results coming from different sets of experiments, using neutrinos from solar, atmospheric, accelerator and reactor sources. At present, each of the known oscillation parameters [the two squared mass gaps (δm2,Δm2) and the three mixing angles (θ12,θ13, θ23)] is dominantly determined by a single class of experiments. Conversely, the unknown parameters (the mass hierarchy, the θ23 octant and the CP-violating phase δ) can currently be constrained only through a combined analysis of various (eventually all) classes of experiments. In the light of recent new results coming from reactor and accelerator experiments, and of their interplay with solar and atmospheric data, we update the estimated Nσ ranges of the known 3ν parameters and revisit the status of the unknown ones. Concerning the hierarchy, no significant difference emerges between normal and inverted mass ordering. A slight overall preference is found for θ23 in the first octant and for nonzero CP violation with sinδ<0; however, for both parameters, such preference exceeds 1σ only for normal hierarchy. We also discuss the correlations and stability of the oscillation parameters within different combinations of data sets. © 2014 American Physical Society.