Topic: Fermion masses: why small and how small

Speaker: Prof. Zhizhong Xing

Coordinates: Classroom 5106, 4pm, Friday, March 26

Abstract: Steven Weinberg, a father of the standard model of particle physics, has been trying to explain the observed pattern of quark and lepton masses since 1972. Starting from some personal comments on the flavor sector of Weinberg's model, which appeared in 1967 as a three-no product, I will briefly introduce two most popular ways of generating fermion masses and (or) making them small enough:tree-level Yukawa interactions and loop-level radiative corrections. The seesaw idea, equivalent to Weinberg's dimension-5 operator, will be highlighted. Then I will focus on a kind of translational flavor symmetry, a quite naive and seemingly exotic approach by generalizing Tsung-Dao Lee and Richard Friedberg's idea in 2006, to link a zero mass of the first fermion family to a possible flavor mixing pattern in the symmetry limit.