High Energy Theory Seminar

The last years have seen remarkable progress in understanding the scattering amplitudes of massless particles in arbitrary dimension. They exhibit structures and a simplicity completely obscured by the Feynman diagram approach, and can be shown to arise from worldsheet models with an auxiliary target space - ambitwistor space. After reviewing the key developments, I will discuss the worldsheet models and derive the loop integrands. Time permitting, I will focus on work in progress on deriving loop amplitudes from Riemann sphere correlators.