Viability of the exact tri-bimaximal mixing at M_{GUT} in SO(10)

Understand

General structures of the charged lepton and the neutrino mixing matrices leading to tri-bimaximal leptonic mixing are determined.

• These are then integrated into an SO(10) model within which detailed fits to fermion masses and mixing angles are given.
• It is shown that one can obtain excellent fits to all the fermion masses and quark mixing angles keeping tri-bimaximal leptonic mixing intact.
• Different perturbations to the basic structure are considered and those which can or which cannot account for the recent T2K and MINOS results on the reactor mixing angle $\theta_{13}^l$ are identified.