Speaker
Description
Track functions describe the collective effect of the fragmentation of quarks and gluons into charged hadrons, making them a key ingredient for jet substructure measurements at hadron colliders where track-based measurements offer superior angular resolution. Unlike DGLAP, the evolution of track functions incorporates correlations between final-state hadrons, and is hence non-linear. We derive the NLO renormalization of the track functions in both $\mathcal{N}=4$ SYM and QCD, which are the first example of evolution equations involving the full $1\to 3$ splitting functions. We clarify how our evolution equations can be reduced to those for the single- and multi-hadron fragmentation functions, and can hence be viewed as the most general collinear evolution equations at NLO. We believe that evolution equations incorporating collinear correlations are an important step beyond DGLAP, and will be relevant for the development of higher order partons showers and for paving the way for precision jet substructure at LHC. Finally, we apply these developments to study correlations of energy flows, and have initiated a discussion of NLL resummation for track energy correlators.
