Résumé
General forms of the Kähler and superpotenials that lead to consistent low energy brokenSupersymmetry originating from N = 1 Supergravity have been classified and used formodel building since more than three decades. We point out the incompleteness of thisclassification when hidden sector vacuum expectation values are of the order of the Planckmass. Focusing in this paper mainly on the case of minimal Kähler potential, we adopta rigorous approach that retrieves on the one hand the known forms, and demonstrateon the other hand the existence of a whole set of new forms for the superpotential ofwhich we give a complete classification. The latter forms involve a new type of chiralsuperfields having the unusual property of belonging neither to the hidden sector nor tothe conventional observable sector. Comparing the obtained forms with the conventionalones, we argue how new possibilities for model building can arise, and discuss the gravitymediation of soft as well as additional hard (but parametrically small) Supersymmetrybreaking, in the presence of the new type of chiral superfields. In the simplest case,we study the vacuum structure, characterize the masses and couplings of the scalarcomponents to the hidden and observable sectors and discuss briefly the physical rolethey could play. In the generic case, we estimate the magnitude and possible consequencesof the hard breaking of Supersymmetry in terms of the interplay between hidden andvisible sectors mass scales.