Ambitwistor superstring in the Green-Schwarz formulation
  In this paper we construct the ambitwistor superstring in the Green-Schwarz formulation. The model is obtained from the related pure spinor version. We show that the spectrum contains only ten dimensional supergravity and that kappa symmetry in a curved background implies some of the standard constraints. 
Osvaldo Chandia, Brenno Carlini Vallilo
hep-th