Simple two Parameter Description of Lepton Mixing

Abstract

We note that a simple two parameter description of lepton mixing is possible which reproduces the features that apparently emerge from global fits at the 1\sigma level: if U_{e3} is non-zero it implies that the solar neutrino mixing parameter \sin^2 \theta_{12} is less than 1/3 by order |U_{e3}|^2. If the CP phase \delta is around \pi it implies that the atmospheric neutrino mixing parameter \sin^2 \theta_{23} is less than 1/2 by order |U_{e3}|. The mixing scheme can be described by a 23-rotation appearing to the right of a tri-bimaximal mixing matrix. We quantify the excellent agreement of the scheme with data statistically, and comment on model building aspects.