Gauge mediation of supersymmetry breaking in the observable sector is
an attractive idea, which naturally alleviates the flavor changing neu
tral current problem of supersymmetric theories. Quite generally, howe
ver, the number and quantum number of the messengers are not known; no
r is their characteristic mass scale determined by the theory. Using t
he recently proposed method to extract supersymmetry-breaking paramete
rs from wave-function renormalization, we derived general formulae for
the soft supersymmetry-breaking parameters in the observable sector,
valid in the small and moderate tan beta regimes, for the case of spli
t messengers. The full leading-order effects of top Yukawa and gauge c
ouplings on the soft supersymmetry-breaking parameters are included. W
e give a simple interpretation of the general formulae in terms of the
renormalization group evolution of the soft supersymmetry-breaking pa
rameters. As a by-product of this analysis, the one-loop renormalizati
on group evolution of the soft supersymmetry-breaking parameters is ob
tained for arbitrary boundary conditions of the scalar and gaugino mas
s parameters at high energies. (C) 1998 Elsevier Science B.V.