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The renormalization-group equations describing the evolution of fermion-Higgs-boson Yukawa coupling constants down from Mₗ in a grand unified theory possess fixed points which may lead to universal predictions for fermion masses independent of symmetry considerations at Mₗ. Our analysis predicts 240 GeV for the fixed-pint t-quark mass. Alternatively, a sufficiently heavy fourth SU (5) generation cannot be ruled out by existing bounds on the number of fermion generations, n₅, and we find fixed-point mass predictions of mₓ219 GeV, m₁215 GeV, and m₄60 GeV.
Christopher T. Hill (Sat,) studied this question.