Abstract
Assuming a minimal seesaw model with two heavy neutrinos (), we examine effects of leptonic violation induced by approximate - symmetric interactions. As long as is subject to the - symmetry, we can choose phases of Dirac mass terms without loss of generality in such a way that these phases arise from - symmetry breaking interactions. In the case that no phase is present in heavy neutrino mass terms, leptonic phases are controlled by two phases and . The similar consideration is extended to blind to the - symmetry. It is argued that subject (blind) to the - symmetry necessarily describes the normal (inverted) mass hierarchy. We restrict ourselves to - symmetric textures giving the tribimaximal mixing and calculate flavor neutrino masses to estimate -violating Dirac and Majorana phases as well as neutrino mixing angles as functions of and . Since and are generated by - symmetry breaking interactions, the -violating Majorana phase tends to be suppressed and is found to be at most radian. On the other hand, the -violating Dirac phase tends to show a proportionality to or to .
7 More- Received 15 October 2007
DOI:https://doi.org/10.1103/PhysRevD.77.075008
©2008 American Physical Society