https://doi.org/10.1140/epjc/s2005-02434-3
Theoretical Physics
S 3 flavor symmetry and leptogenesis
1
Institute for Theoretical Physics, Kanazawa University, 920-1192, Kanazawa, Japan
2
Institut für Physik, Universität Dortmund, Otto-Hahn-Str.4, 44221, Dortmund, Germany
* e-mail: araki@hep.s.kanazawa-u.ac.jp
Received:
28
April
2005
Revised:
2
August
2005
Published online:
25
November
2005
We consider leptogenesis in a minimal S 3 extension of the standard model with an additional Z 2 symmetry in the leptonic sector. It is found that the CP phase appearing in the mass matrix of the left-handed neutrinos is the same as that for the CP asymmetries responsible for leptogenesis. Because of the discrete S 3 x Z 2 flavor symmetries, the CP asymmetries are strongly suppressed. To obtain a realistic size of the baryon number asymmetry in the universe, we therefore have to assume that resonant enhancement of the CP asymmetries takes place, and that three degenerate right-handed neutrino masses of O(10) TeV are present.
© Springer-Verlag, 2006
