Flux-tube physics and scattering amplitudes

by Prof. Andrei Belitsky (Arizona State University - USA)

Tuesday 13 Dec 2016, 15:00 → 16:00 Europe/Rome

Aula Teorici (Dipartimento di Fisica e Astronomia)

Scattering amplitudes in maximally supersymmetric gauge theory receive a dual description in terms of the expectation value of the super Wilson loop stretched on a null polygonal contour. This makes their analysis amenable to nonperturbative techniques. They are studied in a framework of the operator product expansion that encodes propagation of excitations on the (semiclassical) background of the color flux tube stretched between the sides of Wilson loop contour. Their dispersion relations are known to all orders in 't Hooft coupling and form factor couplings to the Wilson loop in a particular tessellation of the loop are known as pentagon transitions. The latter play a role of fundamental building blocks of the formalism and obey a set of bootstrap equations with consistent solutions for any value of the coupling constant. To confirm correctness of these predictions, we calculate the super Wilson loop and demonstrate agreement with perturbative results up to four-loop order in 't Hooft coupling obtained by other means. We also construct systematic expansions at large 't Hooft coupling and provide a glimpse into the structure of scattering amplitude at strong coupling. In particular, we demonstrate the emergence of the minimal area, however, along with additional corrections not visible in TBA analyses.