On the scattering of gluons in the GKP string

TL;DR

This paper calculates the one-loop S-matrix for gluon excitations in the GKP string at strong coupling, confirming integrability predictions and analyzing scheme dependence.

Contribution

It provides the first explicit Feynman diagram computation of the one-loop S-matrix for GKP string excitations and compares it with integrability results.

Findings

Perfect agreement with integrability for scheme-independent parts

Scheme-dependent rational terms match recent proposals

Validates the integrability-based predictions for gluon scattering

Abstract

We compute the one-loop S-matrix for the light bosonic excitations of the GKP string at strong coupling. These correspond, on the gauge theory side, to gluon insertions in the GKP vacuum. We perform the calculation by Feynman diagrams in the worldsheet theory and we compare the result to the integrability prediction, finding perfect agreement for the scheme independent part. For scheme dependent rational terms we test different schemes and find that a recent proposal reproduces exactly the integrability prediction.