Abstract:
Quantum Chromodynamics (QCD) is the theory of strong interactions between quarks and gluons, collectively called partons, mediated by color charges they carry. Hadrons are composite color neutral particles in confined states that comprise much of the visible world around us. However, the processes underlying complex hadron formation from freely moving, deconfined quarks are still not understood from first principles. Many of the emergent properties and dynamic structure of a proton remain unsolved. High-energy particle accelerators enable answering some of these fundamental open questions in QCD. The spin and polarization states of particles and partons can reveal intricate and dynamic structure of a proton via correlations with other properties. Much progress has been made in understanding the spin and transverse momentum structure of the proton with this approach. In high-energy scattering, hadrons often manifest themselves as part of a jet, a collimated array of particles generated by parton shower processes from an energetic parton created in high energy collisions. The past couple of decades saw theoretical breakthroughs in computing the properties of jets and their substructure, and advancements in experimental technique. The collective progress in this field is opening up new ways to study perturbative and (transition to) non-perturbative aspects of QCD at different distance scales.
In this talk, I will review past and recent studies on proton structure and hadron formation at the Large Hadron Collider and Relativistic Heavy Ion Collider, and a path to the Electron-Ion Collider, an actively developing premier project in the U.S. Nuclear Physics program.
