Poles at infinity in scattering amplitudes

by Jaroslav Trnka (UC Davis)

Wednesday 22 Feb 2023, 11:00 → 12:00 Europe/Berlin

Main/0-174 - Auditorium (Main)

Tree-level scattering amplitudes and loop integrands have two types of poles. The first type is located in the low momentum region when Feynman propagators go on-shell which corresponds to the factorization of the amplitude. The exploitation of this property leads to the famous amplitudes tools such as unitarity methods or recursion relations. But there are also other types of poles located at large momenta -- poles at infinity -- which are much less understood and naively the form of the amplitude in this region is not fixed by any physical conditions. This is a very important but difficult problem and the solution, if it exists, must be very complex as there are many different ways to approach the infinite momentum region. We will focus on the poles at infinity in on-shell diagrams, which are gauge-invariant building blocks for amplitudes, and solve this problem for the case of planar amplitudes.