A 3 X 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 $3 \times 2$ 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 $m_{ν_e ν_e} = \frac{\sqrt{Δm^2_{solar}}}{3}$ and $\sqrt{Δm^2_{atm}}$ for the hierarchical and the inverse-hierarchica 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 $U_{e3}$ which is accessible in future baseline neutrino oscillation experiments.