- Center for Theoretical Physics, Department of Physics, Texas A&M University, College Station, TX 77843-4242, USA
We present a general method to obtain specific predictions for the fermion masses and mixings in the low-energy theory of the flipped SU(5) × U(1) superstring model. The condition of unbroken N = 1 supergravity at MPl in the presence of an anomalous UA(1) symmetry gives strong constraints on the parameters of the model. We obtain: (i) a top quark mass between 60 and 100 GeV, with values close to 100 GeV strongly favored; (ii) up- and down-type quark and lepton mass ratios and Cabibbo-Kobayashi-Maskawa mixings, which could be found consistent with their accepted values simultaneously in parameter space; (iii) a direct connection between the hierarchical fermion mass spectrum and baryon decay modes, we find p ? ?+?0, ???+; n ? ?+??, ???0, with ?p ? ?n ? 1035±2y; and (iv) a vanishing bare u quark mass that solves the strong CP problem in this model and is not in conflict with previous expectations. We stress that a full dynamical calculation would unambigously determine these observables and hence constitute a definite test of the model. However, the whole framework is so constrained that crucial information can already be extracted from the model at this stage.
- 1 - natural sciences ; 2 - physics & astronomy ; 3 - nuclear & particles physics
- 1 - sciences appliquees, technologies et medecines ; 2 - sciences exactes et technologie ; 3 - physique ; 4 - physique des particules elementaires et champs
- 1 - Physical Sciences ; 2 - Physics and Astronomy ; 3 - Nuclear and High Energy Physics