# 22nd International Workshop on Weak Interactions and Neutrinos

Sep 14 – 19, 2009
Strada Passo dell'Acqua, 34 - 06134 Bosco PERUGIA, Italy
Europe/Rome timezone

## The magic of four zero neutrino Yukawa textures

Sep 15, 2009, 12:00 PM
20m
Sala Gregorio VI (Strada Passo dell'Acqua, 34 - 06134 Bosco PERUGIA, Italy)

### Sala Gregorio VI

#### Strada Passo dell'Acqua, 34 - 06134 Bosco PERUGIA, Italy

http://win09.lngs.infn.it
Neutrino Physics

PROBIR ROY

### Description

Within the type-I seesaw framework with three heavy right chiral neutrinos and in the basis where the latter and the charged leptons are mass diagonal, we investigate the effects of mu-tau symmetry as well as trbimaximal mixing on the maximally allowed four zero neutrino Yukawa textures which had already led to a predicitve and highly constrained theoretical scheme. A drastic reduction of the seventy two allowed textures is found, leaving only two allowed forms of the light neutrino mass matrix, one of which is on the margin of being ruled out by the present neutrino oscillation data. The other remains a viable candidate for the actual light neutrino mass matrix chosen by nature and will be crucially tested by future measurements of. theta_{13}. Implications for leptogenesis and radiative lepton flavor violating decays are also discussed. The stabilty of these conclusions under running from a high scale, where those symmetries are imposed, to the weak scale is also demonstrated.

### Summary

Mu-tau symmetry is found to reduce the seventy two allowed four zero neutrino Yukawa textures in the standard weak basis to only four. These lead to just two different forms of the light neutrino mass matrix, each being characterized by ttwo real constants and one phase which are highly constrained. Further, a required tribimaximal mixing reduces these three constants to just one with a nearly fixed value. Interesting consequences for both flavored and unflavored leptogenesis as well as radiative lepton flavor violating decays are pointed out. These conclusions
are found to be stable under RG running from a high to the weak scale.

### Co-authors

Dr Ambar Ghosal (Saha Institute of Nuclear Physics) Dr Biswajit Adhikary (Saha Institute of Nuclear Physics)

### Presentation materials

 pdf file Slides