Speaker
Description
Studying the production of charmonium states in hadronic collisions may improve our understanding of the theory describing the strong interaction, known as quantum chromodynamics (QCD). The formation of heavy charm quark pairs takes place during the initial hard partonic scattering and can therefore be calculated using perturbative QCD, while the evolution into a colorless bound state is a non-perturbative process. The production mechanism is described by several theoretical approaches, among them the non-relativistic QCD (NRQCD) effective field theory. NRQCD calculations are capable of describing the measured production yields as a function of the transverse momentum but have difficulties in simultaneously describing the polarization, often referred to as the polarization puzzle. Recently, LHCb and CMS measured the fragmentation of J/psi (the lightest vector onium state in the charm sector) in jets. The measurements found the production of prompt J/psi mesons to be less isolated than predicted. The observed lack of isolation may be related to the polarization puzzle, and further charmonium measurements may help shed a light on our understanding of charmonium production.
The ALICE detector is capable of measuring quarkonium states down to zero transverse momentum both at forward and midrapidity, measuring their decay through the dimuon and dielectron channel, respectively. In this contribution, recent quarkonium measurements in pp collisions will be discussed, with the main focus on the inclusive J/psi cross section measurement at center-of-mass energy 13 TeV. In addition, the future prospects of measuring J/psi in jets will be discussed.
