Speaker
Description
Ultra-peripheral nucleus-nucleus and proton-nucleus collisions (UPC) are mediated by strong
electromagnetic fields, offering the opportunity to study photon-nucleus and photon-proton
processes at RHIC. In particular, coherent $J/\psi$ photoproduction in photon-nucleus interactions
is sensitive to nuclear effects on the gluon density, and exclusive $J/\psi$ photoproduction
in photon-proton collisions can probe the Generalized Parton Distributions in the case
of polarized protons. The $J/\psi$ is an ideal probe of the above phenomena thanks to its large
mass, which allows the use of perturbative Quantum Chromodynamics.
In this talk we present a brief overview of the topic and results on vector meson
photoproduction in Au+Au collisions at 200 GeV and results on $J/\psi$ photoproduction
in p+Au collisions at 200 GeV with a polarized proton beam.
