CP-violation in neutrino oscillations

We study in a quantitative way CP-violating effects in neutrino oscillation experiments in the light of current and future data. Different scenarios w ith three and four neutrinos are worked out in detail including matter effe cts in long baseline experiments and it is shown that in some cases CP-viol ating effects could affect the analysis of a possible measurement. In parti cular in the three neutrino case we find that the effects can be larger tha n expected, at least in long-baseline nu(mu) --> nu(e). Moreover, measuring these effects could give useful information on the solar oscillation frequ ency. In four neutrino scenarios large effects are possible both in the nu( mu) --> nu(tau) and nu(mu) --> nu(e) channels of long-baseline experiments, whereas short-baseline experiments are affected only marginally. (C) 1999 Elsevier Science B.V. All rights reserved.