Phenomenological implications of the mt RGE fixed point for SUSY Higgs boson searches

Abstract

In minimal SUSY-GUT models with $M_{SUSY}\alt 1$ TeV, the renormalization group equations have a solution dominated by the infrared fixed point of the top Yukawa coupling. This fixed point predicts $m_t\simeq (200\; {\rm GeV})\sin \beta $; combined with the LEP results it excludes $m_t\alt 130$ GeV. For $m_t$ in the range 130--160 GeV, it predicts that the lightest scalar $h$ has mass 60--85 GeV (detectable at LEP\,II). At SSC/LHC, each of the five scalars $h$, $H$, $A$, $H^{\pm }$ may be detectable, but not all of them together; in one parameter region none would be detectable.