1303.2668 (Zhiquan Gao et al.)

Y-system for form factors at strong coupling in AdS_5 and with
multi-operator insertions    [PDF]

Zhiquan Gao, Gang Yang

We study form factors in N=4 SYM at strong coupling in general kinematics and with multi-operator insertions by using gauge/string duality and integrability techniques. This generalizes the AdS_3 results of Maldacena and Zhiboedov in two non-trivial aspects. The first generalization to AdS_5 space was motivated by its potential connection to strong coupling Higgs-to-three-gluons amplitudes in QCD which was observed recently at week coupling. The second generalization to multi-operator insertions was motivated as a step towards applying on-shell techniques to compute correlation functions at strong coupling. In this picture, each operator is associated to a monodromy condition on the cusp solutions. We construct Y-systems for both cases. The Y-functions are related to the spacetime (cross) ratios. Their WKB approximations based on a rational function P(z) are also studied. We focus on the short operators, while the prescription is hopefully also applicable for more general operators.

View original: http://arxiv.org/abs/1303.2668