Renormalization group analysis and the top quark mass in the SU(4) × O(4) string model
Authors:
G. K. Leontaris
N. D. Tracas
Affiliation:
Theoretical Physics Division, University of Ioannina, GR-45110, Ioannina, Greece
Physics Department, National Technical University, GR-15773, Zografou, Greece
Abstract:
We perform a two-loop renormalization group analysis for the gauge couplings in the SU(4) × O(4) model. We use the string theory prediction for the unification scale and the experimentally acceptable low energy values for 3 and sin2 θw, to determine the magnitudes of the various symmetry breaking scales as well as the value of the common gauge coupling at the unification scale. We solve the coupled differential system for the gauge and top and bottom Yukawa couplings, and determine the top mass as a function of two parameters which could be chosen to be the ratio of the Higgs VEV's that give masses to the up and down quarks and the value of the top coupling at the unification scale. We find a relatively heavy top quark mass which lies in the range 130mt180 GeV.