The Strong Coupling Constant in Grand Unified Theories
Abstract
Description
The prediction of the strong coupling constant in grand unified theories is reviewed, first in the standard model, then in the supersymmetric version. Various corrections are considered. The predictions in both supergravity-induced and gauge-mediated supersymmetry breaking models are discussed. In the region of parameter space without large fine tuning the strong coupling is predicted to be alpha_s(M_Z) > 0.13. Imposing alpha_s(M_Z)=0.118, we require a unification scale threshold correction of typically -2%, which is accommodated by some GUT models but in conflict with others.
15 pages, 5 figures. Talk given at the SLAC Summer Institute, August, 1996
15 pages, 5 figures. Talk given at the SLAC Summer Institute, August, 1996