Poles at Infinity in on-shell diagrams

by Taro Brown (UC Davis)

Thursday 4 May 2023, 13:30 → 14:30 Europe/Copenhagen

Aud A

There will be a student session at 13:10 before the main talk.

Abstract: It is a well-known fact that locality and unitary forces scattering amplitudes to factorize when taking the momentum of one of the external particles to zero. Not much is known however for the amplitude’s behavior when sending one of the momenta to infinity. In this talk we are going to make modest step towards a prescription of “unitarity at infinity”. We do this by studying on-shell diagrams, which are on-shell gauge invariant objects which appear as cuts of loop integrands in the context of generalized unitarity and serve as building blocks for amplitudes in recursion relations. In the dual formulation, they are associated with cells of the positive Grassmannian. We will describe on-shell diagrams in  N<4 supersymmetric Yang-Mills (SYM) theory and show that there exists a diagrammatic operation that corresponds to sending one of the momenta to infinity.

Seminar_NBI_Brown.pdf