Title: Collinear expansions of color singlet cross sections
Abstract: High-precision measurements at the LHC such as the Drell-Yan process need to be matched by equally precise theory predictions. While QCD calculations for select processes have reached N3LO accuracy, achieving a similar precision for more complicated process still poses a formidable challenge. In my talk, I will briefly review the role of expanding cross sections for such high-precision calculations, before introducing a new expansion in the kinematic limit where all final-state QCD radiation is collinear to one of the incoming protons. I will illustrate that this can significantly simplify higher-order calculations, and show a proof-of-principle application to the Higgs rapidity spectrum at NNLO. Finally, I will show the connection of this technique to transverse-momentum dependent (TMD) factorization, which is relevant e.g. for Drell-Yan production at small transverse momentum, which allows us to calculate the universal TMD PDF at three loops.
