Superspace formulations of ten-dimensional supergravity

We present a new formulation for N = 1, D = 10 supergravity in superspace, in presence of a Lorentz Chern-Simons form. This formulation entails the following properties: it furnishes a solution of the Bianchi identities that is algebraically consistent to all orders in α' at first order it is the simplest formulation proposed so far, and it is therefore most suitable for an explicit higher order analysis; it allows a well defined perturbative expansion in α', in which no poltergeist fields appear; it reconciles the two different classes of first order solutions available in the literature, that until now appeared physically inequivalent.