Yukawa couplings and phenomenology of a three-generation superstring model.

Abstract

Armed with the explicitly calculated Yukawa couplings and knowledge of discrete symmetries we discuss the phenomenology of the three-generation superstring model suggested by Yau. We consider the possibility of CP violation induced through the complex moduli of the Calabi-Yau space (i.e., through the complex parameters in the equations that define the manifold). On analyzing the dimension-four terms in the superpotential in search of F-flat directions, we find that F-flat directions generally lead to extra massless quarks and mirror quarks as well as extra massless leptons and mirror leptons in the low-energy spectrum. We then consider a non-F-flat scenario that has only three quark and lepton generations at low energies. We also analyze other aspects of the model such as constraints of sin/sup 2/theta/sub w/ on the intermediate scale and the neutrino masses and we argue that neutron-antineutron oscillation may be observable in this class of models.