Decoupling limits in multi-sector supergravities

Abstract

Conventional approaches to cosmology in supergravity assume the existence of multiple sectors that only communicate gravitationally. In principle these sectors decouple in the limit M{sub pl}→∞. In practice such a limit is delicate: for generic supergravities, where sectors are combined by adding their Kähler functions, the separate superpotentials must contain non-vanishing vacuum expectation values supplementing the naïve global superpotential. We show that this requires non-canonical scaling in the naïve supergravity superpotential couplings to recover independent sectors of globally supersymmetric field theory in the decoupling limit M{sub pl} → ∞.