CONDITIONS ON SUPERSYMMETRY SOFT-BREAKING TERMS FROM GUTS

We study the effect of integrating out the heavy fields in a supersymmetric GUT which does not contain small mass parameters in the limit of exact supersymmetry. The trilinear (A) and bilinear (B) coefficients of the supersymmetry soft-breaking terms of the low-energy effective theory are related in a simple and model-independent way to those of the underlying theory. From these relations, we obtain the bound Absolute value of B greater-than-or-equal-to 2, which, together with the requirements of stability of the potential and electroweak symmetry breaking, imposes severe constraints on the space of allowed supersymmetric parameters. In models based on supergravity with a flat Kahler metric, we obtain B = 2, instead of the relation B = A - 1 usually used in phenomenological applications. The low-energy theory contains also a supersymmetric mass term mu for the two Higgs doublets, which is of the order of the supersymmetry-breaking scale.