HOW TO LIMIT RADIATIVE-CORRECTIONS TO THE COSMOLOGICAL CONSTANT BY M(SUSY)(4)

Supergravity models are constructed in which the effective low energy theory contains only ''super-soft'' explicit supersymmetry breaking: m asses of the scalars and pseudoscalars within a multiplet are split in opposite directions. With this form of supersymmetry breaking the rad iative corrections of the matter sector to the vacuum energy are bound ed by O(M(Susy)(4)) to all orders in perturbation theory, and we requi re Str M(2) = 0 including the hidden sector. The models are based on K ahler potentials obtained in recent orbifold compactifications, and we describe the construction of realistic theories.