1210.7448 (Masaki Yasue)

Generalized Scaling Ansatz and Minimal Seesaw Mechanism    [PDF]

Masaki Yasue

Generalized scaling in flavor neutrino masses M_{ij} (i,j=e,\mu,\tau) expressed in terms of \theta_{SC} and the atmospheric neutrino mixing angle \theta_{23} is defined by M_{i\tau}/M_{i\mu} = - \kappa_i t_{23} (i=e,\mu,\tau) with \kappa_e=1, \kappa_\mu=B/A and \kappa_\tau=1/B, where t_{23}=tan(\theta_{23}), A=cos^2(\theta_{SC})+sin^2(\theta_{SC})t^4_{23} and B=cos^2(\theta_{SC})-sin^2(\theta_{SC})t^2_{23}. The generalized scaling anzatz predicts the vanishing reactor neutrino mixing angle \theta_{13}=0. It is shown that the minimal seesaw mechanism naturally implements our scaling anzatz. There are textures satisfying the generalized scaling anzatz that yield vanishing baryon asymmetry of the Universe (BAU). Focusing on these textures, we discuss effects of \theta_{13}!=0 to evaluate CP-violating Dirac phase \delta and BAU and find that BAU is approximately controlled by the factor sin^2\theta_{13}sin(2\delta -\phi), where \phi stands for the CP-violating Majorana phase whose magnitude turns out to be at most 0.1.

View original: http://arxiv.org/abs/1210.7448