F-term SUSY Breaking and Moduli

We discuss the coupling of heavy moduli fields to light fields when the dynamics of the latter, absent such couplings, yields metastable vacua. We show that the survival of the vacuum structure of the local model depends nontrivially on the cross-couplings of the two sectors. In particular we find that for "local" models (such as those realized by D-branes in type II string theories) with metastable vacua breaking supersymmetry via F-terms, cross-coupling of the two sectors at an intermediate scale can push the metastable vacuum outside of the regime of the effective field theory. We parametrize the region in which the metastable vacua are safe. We the show that sufficiently small cross-couplings can be made natural. Finally, we briefly discuss the role of moduli in stringy realizations of "retrofitted" SUSY-breaking sectors.