The Infrared Structure of QCD Scattering Amplitudes

by Thomas Becher (University of Bern)

Wednesday 22 Jan 2020, 11:10 → 12:10 Europe/Zurich

Edificio U2, Aula 5017 (Dipartimento di Fisica G. Occhialini, U2, Università degli Studi di Milano-Bicocca)

Amplitudes in theories with massless particles suffer from infrared divergences. While these divergences cancel in physical cross sections, it is nevertheless interesting to understand their structure, since it can be used to predict logarithmically enhanced terms in perturbative computations. In my talk I will explain that the infrared divergences are governed by an anomalous-dimension matrix, which is severely constrained by soft-collinear factorization, non-abelian exponentiation, and the behaviour of amplitudes in collinear limits. I will then present the form of the anomalous-dimension matrix at the four-loop level, which we obtained recently.

 

Seminar_Milano_2019.pdf