QCD factorization from light-ray OPE

Abstract

The energy-energy correlator (EEC) in Quantum Chromodynamics (QCD) serves as an important event shape for probing the substructure of jets in high-energy collisions. A significant progress has been made in understanding the collinear limit, where the angle between two detectors approaches zero, from the factorization formula in QCD and the light-ray Operator Product Expansion (OPE) in Conformal Field Theory. Building upon prior research on the renormalization of light-ray operators, we take an innovative step to extend the light-ray OPE into non-conformal contexts, with a specific emphasis on perturbative QCD. Our proposed form of the light-ray OPE is constrained by three fundamental properties: Lorentz symmetry, renormalization group invariance, and constraints from physical observables. This extension allows us to derive a factorization formula for the collinear limit of EEC, facilitating the future exploration and understanding on subleading power corrections in collinear limit.