HEP Theory Journal Club

Scattering in the saturation regime

Mathieu Giroux

McGill University

The Balitsky-Kovchegov (BK) equation describes the high-energy growth of gauge theory scattering amplitudes and the nonlinear saturation effects that stop it. In this talk, I will elaborate on a new framework to derive loop corrections to this equation “recursively in the loop order” in any gauge theory. The method leverages a recently established equivalence between the physics and (simpler) evolution equation of soft, wide-angle radiation observables, with dimensionally regularized BK Hamiltonians at the Wilson-Fisher point of the theory. As a byproduct of performing this computation to three loops, we develop new technology inspired by cutting-edge Feynman calculus techniques to explicitly evaluate dimensionally regularized Fourier transforms of mixed rational and transcendental functions, applicable beyond the context of this talk.