Connecting leptogenesis to CP violation in neutrino mixings in a tri-bimaximal mixing model

We show that in a recently proposed S3 model for tri-bimaximal mixing pattern for neutrinos, CP violating phases in neutrino mixings are directly responsible for lepton asymmetry ϵℓ. In the exact tri-bimaximal limit, ϵℓ is proportional to one of the Majorana phases whereas in the presence of small deviations from tri-bimaximal pattern, there are two contributions, one being proportional to the Dirac phase and the other to one of the two Majorana phases. In the second case, θ13 is nonzero and correlated with the deviation from maximal atmospheric mixing.