Simplified Unitarity Triangles for the Lepton Sector

Abstract

Encouraged by the latest SNO results, we consider the lepton mixing matrix in the approximation that the nu_2 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 faciltate comparison with experiment.

4 pages, including one figure. v2: corrected typos in Eqs. 1 and 11; added new references to prior, relevant work; re-ordered some references; made 3 minor wording changes