Non-Abelian family symmetries in Pati-Salam unification
  We present a framework of underlying SU(3) x SU(3) family symmetries consistent with Pati-Salam unification and discuss advantages that can justify introducing multiple non-Abelian factors. Advantages include improved vacuum alignment and increased predictivity. We explore in this framework deviations from tri-bi-maximal neutrinos, such as relatively large theta13. 
Ivo de Medeiros Varzielas
hep-ph