Probing Small Bjorken-x Nuclear Gluonic Structure via Coherent J/ψ Photoproduction in Ultraperipheral Pb-Pb Collisions at √s<sub>NN</sub>=5.02 TeV
PHYSICAL REVIEW LETTERS, vol.131, no.26, 2023 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 131 Issue: 26
- Publication Date: 2023
- Doi Number: 10.1103/physrevlett.131.262301
- Journal Name: PHYSICAL REVIEW LETTERS
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, INSPEC, zbMATH, DIALNET
- Istanbul University-Cerrahpasa Affiliated: No
Abstract
Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/psi photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (W-gamma N(Pb)) over a wide range of 40 < W-gamma N(Pb) < 400 GeV. Results are obtained using data at the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 1.52 nb(-1). The cross section is observed to rise rapidly at low WPb.N, and plateau above W-gamma N(Pb) approximate to 40 GeV, up to 400 GeV, entering a new regime of small Bjorken-x (approximate to 6 x 10(-5)) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models.