Status of neutrino oscillations I: the three-neutrino scenario

We present a global analysis of neutrino oscillation data within the three-neutrino oscillation scheme, including in our fit all the current solar neutrino data, the reactor neutrino data from KamLAND and CHOOZ, the atmospheric neutrino data from Super-Kamiokande and MACRO, and the first data from the K2K long-baseline accelerator experiment. We determine the current best fit values and allowed ranges for the three-flavor oscillation parameters, discussing the relevance of each individual data set as well as the complementarity of different data sets. Furthermore, we analyze in detail the status of the small parameters theta_13 and Delta_m21^2 / Delta_m31^2, which fix the possible strength of CP violating effects in neutrino oscillations.