Key points are not available for this paper at this time.
We report a measurement of exclusive J/ψ and ψ(2s) photoproduction in Au+Au ultraperipheral collisions at sNN=200 GeV using the STAR detector. For the first time, (i) the ψ(2s) photoproduction in midrapidity at the Relativistic Heavy-Ion Collider has been experimentally measured; (ii) nuclear suppression factors are measured for both the coherent and incoherent J/ψ production. At average photon-nucleon center-of-mass energy of 25.0 GeV, the coherent and incoherent J/ψ cross sections of Au nuclei are found to be 71±10% and 36±7%, respectively, of that of free protons. The stronger suppression observed in the incoherent production provides a new experimental handle to study the initial-state parton density in heavy nuclei. Data are compared with theoretical models quantitatively.Received 27 November 2023Revised 24 April 2024Accepted 25 June 2024DOI:https://doi.org/10.1103/PhysRevLett.133.052301© 2024 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasQCD in nuclear reactionsRelativistic heavy-ion collisionsStrong interactionNuclear Physics
Abdulhamid et al. (Wed,) studied this question.