A 3 × 2 Texture for Neutrino Oscillations and Leptogenesis

Abstract

In an economical system with only two heavy right-handed neutrinos, we postulate a new texture for 3 x 2 Dirac mass matrix m_D. This model implies one massless light neutrino and thus displays only two patterns of mass spectrum for light neutrinos, namely hierarchical or inverse-hierarchical. Both the cases can correctly reproduce all the current neutrino oscillation data with a unique prediction m(_v_e)(_v_e) = (√( Δm^2_(solar)))/3 and (√( Δm^2_(atm))) for the hierarchical and the inverse-hierarchical cases, respectively, which can be tested in next generation neutrino-less double beta decay experiments. Introducing a single physical CP phase in m_D, we examine baryon asymmetry through leptogenesis. Interestingly, through the CP phase there are correlations between the amount of baryon asymmetry and neutrino oscillation parameters. We find that for a fixed CP phase, the hierarchical case also succeeds in generating the observed baryon asymmetry in our universe, plus a non-vanishing U(_e_3) which is accessible in future baseline neutrino oscillation experiments.