A three-parameter neutrino mass matrix with maximal CP violation

Using the seesaw mechanism, we construct a model for the light-neutrino Majorana mass matrix which yields trimaximal lepton mixing together with maximal CP violation and maximal atmospheric-neutrino mixing. We demonstrate that, in our model, the light-neutrino mass matrix retains its form under the one-loop renormalization-group evolution. With our neutrino mass matrix, the absolute neutrino mass scale is a function of |Ue3| and of the atmospheric mass-squared difference. We study the effective mass in neutrinoless ββ decay as a function of |Ue3|, showing that it contains a fourfold ambiguity.