Coupling Constant and Yukawa Coupling Unifications: Uncertainties and Constraints

الأصل · EN

The status of coupling constant unification (with and without a unification of Yukawa couplings) is discussed. Uncertainties associated with the input coupling constants, mb and mₜ, threshold corrections at the low and high scale, and possible nonrenormalizable operators are described and a discrepancy between effective and physical scales is pointed out. Theoretical uncertainties in the predictions of αₛ(MZ), mb, and the unification scale, MG, are discussed and estimated. Constraints on the super-partner spectrum are found to be weak if uncertainties associated with the high-scale are included. However, requiring hb = hτ at MG excludes 3 < β< 40 (for mₜ < 200 GeV).