Abstract :
A right-handed stop not much heavier or even lighter than the Z boson has today desirable phenomenological consequences. We study how it can result within the usual radiative scenario of electroweak symmetry breaking. A restriction on the gaugino mass parameters, M2 ≲ 0.3m0, arises if soft terms satisfy relations suggested by unification theories. Moreover, requiring to get a light stop without unnatural fine-tunings below the per-cent level, we obtain another more interesting upper bound on the chargino mass, Mχ ≲ Mz, and we derive interesting conclusions about the masses of the gluino, M3 ∼ (150 ÷ 300) GeV, of the heavy stop, MT ∼ (250 ÷ 500) GeV, and of the left/right mixing angle in the stop sector, |θt| ≲ 0.3.
