Dr. Federico Buccioni

Universality of QCD scattering amplitudes at high energy

Abstract

Scattering processes in the high-energy – or Regge – limit provide a rich laboratory to probe the structure of gauge theories, such as QCD, both at amplitude and cross-section level. This regime is closely tied to the BFKL evolution equation, and studying QCD in this limit yields insights to extend it beyond the current state of the art. In this talk, I will discuss the factorisation properties and universal building blocks of high-energy scattering amplitudes at two-loop order. After revisiting key ideas from Regge theory, I will introduce the Balitsky–JIMWLK formalism in the dilute regime. I will argue how this describes amplitudes through correlators of infinite Wilson lines, and show how it can be extended to next-to-next-to-leading logarithmic accuracy. Finally, I will present the two-loop correction to the Balitsky–JIMWLK gluon-emission vertex in QCD and N=4 super Yang–Mills.