Exploring New Tests of Hadron Production using Jet Substructure

While bound states of cc and bb pairs called quarkonia have been studied for nearly a half-century, their production is still not well understood. This talk will describe recent efforts to use techniques from two effective field theories of QCD, the Soft-Collinear Effective Theory (SCET) and Non-relativistic QCD (NRQCD), to study how quarkonia are produced within jets in high energy collisions. Recent work has shown that for jets that contain quarkonia, the substructure of the jet may provide a laboratory in which to study the underlying production mechanisms of the quarkonia. The energy distribution of a hadron identified within a jet of measured substructure is given by a Fragmenting Jet Function (FJF). This talk will discuss the development of the FJF formalism within SCET to study the production of specific hadrons such as quarkonia within jets of certain substructure. This formalism may provide new observables that can be used to solve long-outstanding puzzles in quarkonium production.