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2007.
FERMION MASSES AND THE UV CUTOFF OF THE MINIMAL REALISTIC SU(5)
We investigate the predictions for fermion masses in the min imal realistic non-supersymmetric SU(5) model with the Standard Model matter content. The possibili ty to achieveb− τ unification is studied taking into account all relevant effects. In additi on, we show how to establish an upper bound on the ultraviolet cutoffΛ of the theory which is compatible with the Yukawa couplings a t the grand unified scale and proton decay. We find Λ ≃ 10 GeV, to be considered a conservative upper bound on the cutoff. We also provide up-to-date values of all the fe rmions masses at the electroweak scale.