Joint INFN-UNIMI-UNIMIB Pheno Seminars
The Infrared Structure of QCD Scattering Amplitudes
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Europe/Zurich
Edificio U2, Aula 5017 (Dipartimento di Fisica G. Occhialini, U2, Università degli Studi di Milano-Bicocca)
Edificio U2, Aula 5017
Dipartimento di Fisica G. Occhialini, U2, Università degli Studi di Milano-Bicocca
Piazza della Scienza, 3, 20126 Milano MI, Italia
Description
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.