Seminar by Gherardo Vita "Collinear Expansion of Cross Sections and the EEC at N3LL' in QCD"

by Gherardo Vita (MIT and SLAC)



In this seminar I'll show how to efficiently expand hadronic cross sections in the collinear limit. This method can be used in pp collisions, semi-inclusive DIS (SIDIS) processes, and color singlet decays as the ones resulting from electron-positron annihilation. This technique can be used for the study of different physical observables such as the approximation of rapidity distributions at the LHC, the calculation of N-jettiness beam functions as well as TMDPDFs and fragmentation functions at N3LO. In this talk I'll focus on its application to the calculation of the back-to-back asymptotic of the Energy-Energy Correlation (EEC). I'll present the calculation of this limit at three loops in QCD, matching the order of the results obtained in N=4 sYM, and its resummation at N3LL', which constitutes the highest level of accuracy for the resummation of an event shape to date.