#### Augusto Sagnotti (SNS & INFN, Pisa)

## AdS vacua from dilaton tadpoles and form fluxes

Abstract

I shall describe how unbounded three-form fluxes can lead to families of AdS_3 x S_7 vacua, with constant dilaton profiles, in the USp(32) string model with ''brane supersymmetry breaking'' and in the U(32) 0'B model, if their (projective-)disk dilaton tadpoles are taken into account. I shall also describe how, in the SO(16) x SO(16) heterotic model, if the torus vacuum energy is taken into account, unbounded seven-form fluxes can support similar AdS_7 x S_3 vacua, while unbounded three-form fluxes, when combined with internal gauge fields, can support AdS_3 x S_7 vacua, which continue to be available even if the torus vacuum energy is neglected. In addition, special gauge field fluxes can support, in the SO(16) x SO(16) heterotic model, a set of AdS_n x S_(10-n) vacua, for all n=2,..,8. String loop and alpha' corrections appear under control when large form fluxes are allowed.