Zhongbo Kang, Los Alamos National Laboratory
Wednesday, August 3, 2016 - 2:00pm to 3:00pm
At present day hadron colliders, collimated jets of hadrons are abundantly produced and a large fraction of the currently investigated observables at the Large Hadron Collider (LHC) involve jets. The experiments at the LHC measure both the inclusive jet production cross sections, as well as a variety of jet substructure observables. Jets and jet substructure have emerged as an ideal testing ground to study the fundamental properties of Quantum Chromodynamics (QCD). In this talk, I introduce a new kind of jet functions — called “semi-inclusive jet functions”, which describe the jet initiated by a parton acquiring a momentum fraction of the parton energy. I demonstrate that it is these semi-inclusive jet functions that are relevant for the calculations of the cross section, as well as the substructure for “inclusive” jet production. Within the Soft Collinear Effective Theory (SCET), I show that they follow time-like DGLAP evolution equations, which can be used to perform the small jet radius R resummation. We further discuss the jet substructure using hadron distribution inside the jet as a concrete example. Our formalism describes the LHC data very well. I point out the immediate applications for medium modification of jets and jet substructure in heavy ion collisions. This work is closely related to the seminal work by Ellis et.al. for exclusive jet production.