Abstract: 

     The future of the LHC program calls for precise theoretical predictions for cross sections beyond the current state of the art, e.g. NNLO corrections for 2-to-3 processes with multiple final-state massive bosons. A promising new method is direct numerical integration in momentum space with contour deformation. This requires subtraction of IR and UV singularities at a fully local level, i.e. point-by-point in loop momentum space. As the simplest example, we investigate the production of n photons in massless electron-positron annihilation in QED and develop universal counterterms to remove singularities. The counterterms are carefully designed to make factorization properties manifest prior to loop integration and can be integrated analytically in dimensional regularization with established methods.

Introduction:

     Mao Zeng obtained his PhD at the Stony Brook University, New York in 2015. He has worked as a postdoctoral researcher at UCLA and is now at ETH Zurich. His research focuses on precision calculations in quantum field theory, bringing together modern methods for scattering amplitudes, state-of-the-art loop integration techniques, and effective field theories which helps untangle infrared divergences in gauge theory and gravity. See http://old.inspirehep.net/author/profile/M.Zeng.1 .