Masses and Mixing Angles of Quarks and Leptons and a Novel Origin of CP Violation
Prof. Dr. Mu-Chun Chen (Department of Physics and Astronomy, UC Irvine)
The Standard Model of particle physics has been tested experimentally to a high degree of accuracy. Despite its successes in describing particle interactions at very short distances, it has many glaring deficiencies. Among these are the many free parameters that parametrize fermion masses and mixings. The origin of fermion mass hierarchy and mixing still remains one of the great mysteries in particle physics. Even though the fermion masses are generated by the Higgs mechanism, the Higgs mechanism by itself does not explain the observed mass hierarchy and mixing patterns. The discovery of non-zero neutrino masses leads to yet another puzzle: why the neutrino masses are so small when compared to other fermions, and why two of the three neutrino mixing angles are so large when compared with their quark counterpart. In this talk, I will discuss how these outstanding questions can be addressed in a supersymmetric grand unified model combined with a finite group family symmetry. In particular, I will describe a model which gives rise to realistic masses and mixing angles of all observed fermions, including the neutrinos, with a significantly reduced number of parameters. In this model, CP violation is entirely geometrical in origin. This leads to interesting implications for the generation of the matter-antimatter asymmetry in the Universe.