Simplified unitarity triangles for the lepton sector

Encouraged by the latest SNO results, we consider the lepton mixing matrix in the approximation that the ν₂ mass eigenstate is trimaximally (democratically) mixed. This suggests a new parameterization of the remaining mixing degrees of freedom, which eschews mixing angles, dealing instead, directly with the complex parameter U_e3 of the mixing matrix. Unitarity triangles then take a particularly simple form, which we hope will facilitate comparison with experiment.