Worldsheet scattering in AdS5 x S5

We calculate the S-matrix in the gauge-fixed sigma-model on AdS(5) x S-5 to the leading order in perturbation theory, and analyze how supersymmetry is realized on the scattering states. A mild nonlocality of the supercharges implies that their action on multi-particle states does not follow the Leibniz rule, which is replaced by a nontrivial coproduct. The plane wave symmetry algebra is thus naturally enhanced to a Hopf algebra. This structure mirrors that of the large't Hooft coupling expansion of the S-matrix for the spin chain in the dual super-Yang-Mills theory.