Abstract :
We show that the usual dilaton dominance scenario, derived from the tree level Kähler potential, can never correspond to a global minimum of the potential at V = 0. Similarly, under very general assumptions it cannot correspond to a local minimum either, unless a really big conspiracy of different contributions to the superpotential W(S) takes place. These results, plus the fact that the Kähler potential is likely to receive sizeable string non-perturbative contributions, strongly suggest to consider a more general scenario, leaving the Kähler potential arbitrary. In this way we obtain generalized expressions for the soft breaking terms but a predictive scenario still arises. Finally, we explore the phenomenological capability of some theoretically motivated forms for non-perturbative Kähler potentials, showing that it is easy to stabilize the dilaton at the realistic value S ∼ 2 with just one condensate and no fine-tuning.
