Speaker: Alfredo Aranda (College of Williams and Mary)

Date: Wed Jan 24, 2001, 4.30 pm
Location: Wean 7316

Title: A Minimal Theory of Flavour 

Abstract: 

In an attempt to understand the observed patterns of lepton and quark
masses, models invoking a flavor symmetry $G_f$, under which the Standard
Model generations are charged, have been proposed. One particularly
successful symmetry, U(2), has been extensively discussed in the
literature. The Yukawa matrices in models based on this symmetry reproduce 
the observed mass ratios in the lepton and quark sectors. The features of
the symmetry that determine the texture of the Yukawa matrices can be found
in other symmetries as well. We present a model based on a minimal, 
non-Abelian discrete symmetry that reproduces the Yukawa matrices associated
with U(2) theories of flavor. In addition to reproducing the mass and 
mixing angle relations obtained in such theories, the different representation
structure of our new horizontal symmetry allows for solutions to the solar and
atmospheric neutrino problems.