Flavour models for TM1 lepton mixing
  We present a framework for lepton flavour models such that the first column of the lepton mixing matrix is (2,-1,-1)/sqrt(6). We show that the flavour symmetry group adequate for this purpose is S4. Our models are based on a vacuum alignment that can be obtained in a supersymmetric framework. 
Ivo de Medeiros Varzielas, Lu\'is Lavoura
hep-ph