On Classical Stability with Broken Supersymmetry

Understand

We study the perturbative stability of four settings that arise in String Theory, when dilaton potentials accompany the breaking of Supersymmetry, in the USp(32) and U(32) orientifold models, and also in the heterotic SO(16)xSO(16) model.

• The first two settings are a family of AdS3xS7 orientifold vacua and a family of AdS7xS3 heterotic vacua, supported by form fluxes, with small world-sheet and string-loop corrections within wide ranges of parameters.
• In both cases we find some unstable scalar perturbations, as a result of mixings induced by fluxes, confirming for the first class of vacua a previous result.
• However, in the second class they only affect the l=1 modes, so that a Z2 projection induced by an overall internal parity suffices to eliminate them, leading to perturbative stability.