From webs to polylogs
Wed, Nov. 27th 2013, 14:15
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
I review the recent progress in studying long-distance singularities in gauge-theory scattering amplitudes in terms of Wilson lines. I will begin by reviewing the non-Abelian exponentiation theorem, which has been recently generalised to the case of multi-leg amplitudes. I will sketch the method we used to prove the theorem and illustrate how connected colour factors emerge in the exponent in webs that are formed by sets of multiple-gluon-exchange diagrams. In the second part of the talk I will report on recent progress in evaluating the corresponding integrals, where a major simplification is achieved upon formulating the calculation in terms of subtracted webs. I will argue that the contributions of all multiple-gluon-exchange diagrams to the soft anomalous dimension take the form of products of specific polylogarithmic functions, each depending on a single cups angle.