L. Clavelli et al., GLUINO CONTRIBUTION TO THE 3-LOOP BETA-FUNCTION IN THE MINIMAL SUPERSYMMETRIC STANDARD MODEL, Physical review. D. Particles and fields, 55(7), 1997, pp. 4268-4272
We deduce the gluino contribution to the three-loop QCD beta function
within the minimal supersymmetric standard model (MSSM) from its stand
ard QCD expression. The result is a first step in the computation of t
he full MSSM three-loop beta function. In addition, in the case of a l
ight gluino it provides the strong three-loop SUSY correction to the e
xtrapolation of the strong coupling constant from the low energy regim
e to the Z region and up to the squark threshold.