Understanding the J/psi Production Mechanism at PHENIX

Abstract

<p>The large mass of the charm quark, along with the abundance of J/ψ mesons observed from proton-proton collisions at PHENIX, allow for new measurements which are sensitive to basic properties of QCD. Two measurements are presented in this document: a transverse single-spin asymmetry (SSA) of J/ψ production and the angular distribution for decay leptons in various reference frames. The decay distribution is directly sensitive to the J/ψ production mechanism, while the transverse SSA is also sensitive to the distribution of gluons in a transversely polarized proton. Taken together, the two measurements provide a wealth of information about the formation of a J/ψ meson.</p>