Webs and Unitarity

Unitarity-based methods have been highly successful in recent years, leading to efficient reconstruction methods of gauge-theory amplitudes from their generalised cuts. A so-far less-developed application of cut techniques is the computation of individual Feynman integrals from the corresponding (generalised) cuts. Progress in this direction was recently made in 1401.3546, which studied multiple unitarity cuts in view of the present understanding of iterated integrals and their co-product structure.

In recent years we have also seen progress on long-distance singularities of gauge-therory scattering amplitudes. In particular, configuration-space methods have been developed for evaluating web diagrams involving multiple Wilson lines (for a recent review, see 1407.5164). These calculations showed that webs have a very simple analytic structure, suggesting that cut techniques could be useful. The purpose of this mini-workshop is to review the recent work in this area, focusing on the use of unitarity methods in the context of webs. We will be hosting the NIKHEF group: Eric Laenen, Kasper Larsen and Robbert Rietkerk, as well as Chris White (Glasgow). The workshop is co-funded by NIKHEF and the Higgs Centre.

The programme includes six lectures, all accessible to first year PhD students, and ample time for discussions. Participation is open to all. PhD students are strongly encouraged to participate. All participants are requested to register.

Talk Schedule:

Monday morning
9:30-10:00 Einan Gardi - Introduction
10:00-11:00 Samuel Abreu - Reconstruction of Feynman integrals from cuts
11:00-12:00 Discussion

Monday afternoon
14:00-14:30 Kasper Larsen - Wilson lines and Unitarity
14:30-15:30 Robbert Rietkerk - Cuts in configuration space
15:30-16:30 Eric Laenen - Discussion

Tuesday morning
10:00-11:00 Chris White - Multiple Gluon Exchange Webs
11:00-12:00 Andries Waelkens - Sewing webs from cuts

Tuesday afternoon: Discussions

Wednesday morning
9:30-11:00 Eric Laenen - Factorization Proofs