Constraints From Gauge Coupling Unification On The Scale Of   Supersymmetry Breaking
  We reanalyze precision LEP data and coupling constant unification in the minimal supersymmetric $SU(5)$ model including the evolution of the gaugino masses. We derive general bounds on the primordial gaugino supersymmetry-breaking mass-scale $m_{1/2}$ in terms of the various input parameters. The model cannot accommodate $m_{1/2}<1\TeV$ for values of $\as < 0.115$, even for extreme $1-\sigma$ values of the other inputs. We emphasize the sensitivity of this type of calculations to the various input parameters. 
John Ellis, S. Kelley and D. V. Nanopoulos