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HEP/Astro Journal Club -- Friday, 22 February 2002

Neutrino anarchy and leptogenesis

Si-Yeon Kim (Indiana)


We show that one can describe the quark and lepton masses with a single anomaly-free U(1) flavor symmetry. This can be seen to arise from inside the E6 symmetry group in such a way that it commutes with the SU(5) grand unified gauge group. The scenario does not distinguish between the left-handed lepton doublets and hence is a model of neutrino anarchy. It can therefore account for the large mixing observed in atmospheric neutrino experiments and predicts that the solar neutrino oscillation data is consistent with the large mixing angle solution of matter-enhanced oscillations.

We relate leptogenesis in a class of theories to low-energy experimental observables: quark and lepton masses and mixings. With reasonable assumptions motivated by grand unification, one can show that the CP-asymmetry parameter takes a universal form. Furthermore, the dilution mass is related to the light neutrino masses. Overall, these models offer an explanation for a lepton asymmetry in the early universe.

12:30, Smith Lab 4079

George T. Fleming ( gfleming@mps.ohio-state.edu ), last updated 20 February 2002.

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