  Within the Minimal Supersymmetric Grand Unified Theory (MSGUT) masses of the
predicted supersymmetric particles are constrained by the world averaged values
of the electroweak and strong coupling constants, the lower limits on the
proton lifetime,the lower limit on the lifetime of the universe, which implies
an upper limit on the dark matter density, the electroweak symmetry breaking
originating from radiative corrections due to the heavy top quark, and the
ratio of the masses of the b-quark and tau-lepton. A combined fit shows that
indeed the MSGUT model can satisfy all these constraints simultaneously and the
corresponding values for all SUSY masses are given within the minimal model,
taking into account the complete second order renormalisation group equations
for the couplings and the one-loop corrections to the Higgs potential for the
calculation of the Z-mass and the Higgs masses. These one-loop corrections to
MZ have been derived explicitly as function of the stop- and top masses and
found to be small for the best solution, but unnaturally large for the 90% C.L.
upper limits on the SUSY masses.
