Studies of generalized transverse momentum dependent gluon distributions in diffractive processes

Abstract
Hadrons, such as protons and neutrons, constitute the dominant components of the visible matter around us. Understanding their internal structures, consisting of quarks and gluons, collectively referred to as partons, requires high energy hadron collisions to probe their contents. At high energies, where hadrons essentially move at high velocities, gluons are predominantly produced, rendering quark contributions negligible. The gluon distributions are described by parton distribution functions (PDFs) dependent on variables related to the parton and hadron momentum. Including more variables in these functions offers a more complete description of the partons. The six dimensional Generalized Transverse Momentum Distribution PDFs (GTMDs), as the counterpart of the Wigner “mother distribution”, provide a comprehensive depiction of parton distribution inside hadrons. We constructed a generic gluon GTMD model based on established models that have successfully described existing data and introduced a few parameters to fit the data. Our model adequately describes diffractive dijet and J/ψ production data, although some tension remains if one aims for a simultaneous description. Future data from experiments on both existing and new accelerators being built can help clarify this tension.