Worldsheet two- and four-point functions at one loop in AdS3/CFT2

In this note we study worldsheet two- and four-point functions at the one-loop level for the type IIA superstring in AdS3×S3×M4AdS3×S3×M4. We first address the regularization ambiguity that appears in the dispersion relation derived from integrability. We demonstrate that only the regulator treating all fields equally respects worldsheet supersymmetry. This is done in an implicit regularization scheme where all divergent terms are collected into master tadpole-type integrals. We then investigate one-loop two-body scattering on the string worldsheet and verify that a recent proposal for the dressing phase reproduces explicit worldsheet computations. All calculations are done in a near-BMN like expansion of the Green–Schwarz superstring equipped with quartic fermions.