Fermion masses and proton decay in string - inspired SU
نویسنده
چکیده
We present a supersymmetric model of fermion masses with SU(4)×SU(2)2×U(1)X gauge group with matter in fundamental and antisymmetric tensor representations only. The up, down, charged lepton and neutrino Yukawa matrices are distinguished by different Clebsch-Gordan coefficients due to contracting over SU(4) and SU(2)R indices. We obtain a hierarchical light neutrino mass spectrum with bi-large mixing. The condition that anomalies be cancelled by a Green-Schwarz mechanism leads to fractional U(1)X charges which exclude B violation through dimension-4 and -5 operators.
منابع مشابه
Flipped SU(5): Origins and Recent Developments
We present an account of the early developments that led to the present form of the flipped SU(5) string model. We focus on the method used to decide on this particular string model, as well as the basic steps followed in constructing generic models in the free fermionic formulation of superstrings in general and flipped SU(5) in particular. We then describe the basic calculable features of the...
متن کاملImplications of Anomalous U ( 1 ) Symmetry in Unified Models : the Flipped SU ( 5 ) × U ( 1 ) Paradigm
A generic feature of string-derived models is the appearance of an anomalous Abelian U (1) A symmetry which, among other properties, constrains the Yukawa couplings and distinguishes the three families from each other. In this paper, we discuss in a model-independent way the general constraints imposed by such a U (1) A symmetry on fermion masses, R-violating couplings and proton-decay operator...
متن کاملCERN-TH/2001-0281 DFPD 01/TH/04 SU(5) Grand Unification in Extra Dimensions and Proton Decay
We analyse proton decay in the context of simple supersymmetric SU(5) grand unified models with an extra compact spatial dimension described by the orbifold S/(Z2 × Z ′ 2). Gauge and Higgs degrees of freedom live in the bulk, while matter fields can only live at the fixed point branes. We present an extended discussion of matter interactions on the brane. We show that proton decay is naturally ...
متن کاملAnomalous U(1): Solving Various Puzzles Of MSSM And SU(5) GUT
We discuss how an anomalous U(1) symmetry when appended to MSSM and SUSY GUTs [e.g. SU(5)] can help overcome a variety of puzzles related to charged fermion masses and mixings, flavor changing processes, proton decay and neutrino oscillations. Proton lifetime for SU(5) GUT, in particular, is predicted in a range accessible to the ongoing or planned searches. To appear in the proceedings of NOON...
متن کاملNeutrino Masses and Mixing Angles in a Realistic String-inspired Model
We analyse a supersymmetric string-inspired model of all fermion masses and mixing angles based on the Pati-Salam SU(4)×SU(2)L×SU(2)R gauge group supplemented by a U(1)X flavour symmetry. The model involves third family Yukawa unification and predicts the top mass and the ratio of the vacuum expectation values tanβ. The model also provides a successful description of the CKM matrix and predicts...
متن کامل