Light Higgsinos, Heavy Gluino and $b-\tau$ Quasi-Yukawa Unification: Will the LHC find the Gluino?

Abstract

A wide variety of unified models predict asymptotic relations at $M_{GUT}$ between the b quark and $\tau$ lepton Yukawa couplings. Within the framework of supersymmetric SU(4) $\times$ SU(2)$_L \times$ SU(2)$_R$, we explore regions of the parameter space that are compatible with b-$\tau$ quasi-Yukawa unification and the higgsinos being the lightest supersymmetric particles ($\lesssim$ 1 TeV). Among the colored sparticles, the stop weighs more than 1.5 TeV or so, whereas the squarks of the first two families are signifcantly heavier, approaching 10 TeV in some cases. The gluino mass is estimated to lie in the 2-4 TeV range which raises the important question: Will the LHC find the gluino?