HOW TO LIMIT RADIATIVE CORRECTIONS TO THE COSMOLOGICAL CONSTANT BY M^4_Susy

Abstract

Supergravity models are constructed in which the effective low energy theory contains only ``super-soft'' explicit supersymmetry breaking: masses of the scalars and pseudoscalars within a multiplet are split in opposite directions. With this form of supersymmetry breaking the radiative corrections of the matter sector to the vacuum energy are bounded by ${\cal O} (M^4_{Susy})$ to all orders in perturbation theory, and we require $Str M^2 = 0$ 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.