Three-neutrino mixing after the first results from K2K and KamLAND

We analyze the impact of the data on long-baseline ${\nu }_{\mu }$ disappearance from the K2K experiment and reactor ${\overline{\nu }}_e$ disappearance from the KamLAND experiment on the determination of the leptonic three-generation mixing parameters. Performing an up-to-date global analysis of solar, atmospheric, reactor, and long-baseline neutrino data in the context of three-neutrino oscillations, we determine the presently allowed ranges of masses and mixing and we consistently derive the allowed magnitude of the elements of the leptonic mixing matrix. We also quantify the maximum allowed contribution of $\Delta m_{21}^2$ oscillations to CP-odd and CP-even observables at future long-baseline experiments.