All-loop worldsheet S matrix for AdS3 × S3 × T4

Abstract

We obtain the all-loop worldsheet S matrix for fundamental excitations on AdS3 × S3 × T4 by studying the off-shell symmetry algebra of the superspace action in lightcone gauge. The massless modes, unaccounted for in earlier works, are automatically included in our treatment. Their exact dispersion relation is found to be non-relativistic, of giant-magnon form and their scattering is naturally well-defined. This opens the way to a complete investigation of AdS3/CFT2 integrability.