On supersymmetry breaking in string theory from gauge theory in a throat

We embed the supersymmetry breaking mechanism in N=1 SQCD of hep-th/0602239in a smooth superstring theory using D-branes in the background R^4 \timesSL(2)_{k=1}/U(1) which smoothly captures the throat region of an intersectingNS5-brane configuration. A controllable deformation of the supersymmetricbranes gives rise to the mass deformation of the magnetic SQCD theory on thebranes. The consequent instability on the open string worldsheet can befollowed onto a stable non-supersymmetric configuration of D-branes whichrealize the metastable vacuum configuration in the field theory. The new braneconfiguration is shown to backreact onto the background such as to producedifferent boundary conditions for the string fields in the radial directioncompared to the supersymmetric configuration. In the string theory, this isinterpreted to mean that the supersymmetry breaking is explicit rather thanspontaneous.Comment: 29 pages, harvmac, 8 figures; v2 typos corrected, reference adde