Loop Integrands from the Riemann sphere

by Yvonne Geyer (Oxford)

Thursday 28 Apr 2016, 14:15 → 15:15 Europe/Berlin

SR 2 (DESY Hamburg)

Worldsheet formulations of  quantum field theories have had wide ranging impact on the study of scattering amplitudes. However, the mathematical framework becomes very challenging on the higher-genus worldsheets required to describe loop effects. I will describe how in such worldsheet models based on the scattering equations, formulae on higher-genus surfaces can be transformed to remarkably simple expressions on the Riemann sphere. My talk will focus on both supersymmetric and non-supersymmetric Yang-Mills theory and gravity, and discuss a proposal for the all-loop integrand.