1205.1355 (Biswajit Adhikary et al.)

Scaling ansatz, four zero Yukawa textures and large $θ_{13}$    [PDF]

Biswajit Adhikary, Mainak Chakraborty, Ambar Ghosal

We have investigated four zero and five zero Yukawa textures of neutrino in addition with scaling ansatz within the framework of type I seesaw mechanism. In case of four zero textures out of 126 matrices only 12 matrices remain four zero. Again out of 12 textures 3 of them are discarded because of generation of two mixing angles zero at the leading order. In the same way we found that there are 12 five zero textures which remain five zero under scaling ansatz. Again out of these 12 matrices we have discarded 6 decoupled cases. So finally we have analyzed the remaining 9(four zero) and 6(five zero) cases parametrising them in a convenient way. As a property of the scaling ansatz one mixing angle($\theta_{13}$) and one mass eigenvalue($m_{3}$) is obtained zero after diagonalisation of the mass matrices. We have constrained the parameter space with other neutrino data. In view of present experimental results of large $\theta_{13}$, breaking of scaling ansatz is necessary to generate nonzero $\theta_{13}$ and we have incorporated such breaking through a dimensionless parameter $\epsilon$ without disturbing four zero nature nature of $m_D$. We have seen that there are enough parameter space for generation of large $\theta_{13}$ keeping constraint with other neutrino oscillation experimental results and valid first order perturbation ($\epsilon\le0.1$). We also obtain nonzero $J_{CP}$ and $\delta$. They are constrained from additional bound of $\theta_{13}$. We have also studied Baryogenesis via Leptogenesis in the above textures, however, most of the parameters have not changed substantially, only sign of the phase (only phase present in this model) is fixed with the constraint from baryogenesis.

View original: http://arxiv.org/abs/1205.1355