CP violation effects and high energy neutrinos

This work discusses critically the prospects of measuring CP and T violation effects in high energy neutrino factories. For this purpose we develop, in the standard framework with three neutrino flavors, simple expressions for the oscillation probabilities in matter that are valid for high E_nu. All CP violating effects vanish as E_nu^(-3) and are very difficult to detect with high energy neutrinos. A significantly easier task is the determination of the absolute value |delta| of the phase in the neutrino mixing matrix that controls the CP and T violation effects, performing precision measurements of the CP and T conserving part of the oscillation probabilities.