Abstract
Group theoretical factors from GUT symmetry breaking can lead to predictions for the ratios of quark and lepton masses at the unification scale. Due to supersymmetric (SUSY) threshold corrections the viability of such predictions can depend strongly on the SUSY parameters. We derive possible new predictions for the GUT scale ratios m μ /m s , y τ /y b and y t /y b and compare them with the experimentally allowed ranges for three common SUSY breaking scenarios. © 2010 American Institute of Physics.