Probing small Bjorken-x nuclear gluonic structure via coherent J/ψ photoproduction in ultraperipheral Pb-Pb collisions at √&lt;em&gt;s&lt;/em&gt;&lt;sub&gt;NN&lt;/sub&gt;=5.02  TeV

Tumasyan, A.; Adam, W.; Andrejkovic, J.W.; Bergauer, T.; Chatterjee, S.; Damanakis, K.; Dragicevic, M.; Escalante Del Valle, A.; Hussain, P.S.; Jeitler, M.; Bevilacqua, T.; Caminada, L.; Ebrahimi, A.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H.C.; Kotlinski, D.; Lange, C.; Missiroli, M.; Noehte, L.; Rohe, T.; Zhokin, A.

doi:10.1103/PhysRevLett.131.262301

Probing small Bjorken-x nuclear gluonic structure via coherent J/ψ photoproduction in ultraperipheral Pb-Pb collisions at √s_NN=5.02 TeV

Tumasyan A, Adam W, Andrejkovic JW, Bergauer T, Chatterjee S, Damanakis K, Dragicevic M, Escalante Del Valle A, Hussain PS, Jeitler M, Bevilacqua T, Caminada L, Ebrahimi A, Erdmann W, Horisberger R, Ingram Q, Kaestli HC, Kotlinski D, Lange C, Missiroli M, Noehte L, Rohe T, Zhokin A, et al.

Citation

Tumasyan, A., Adam, W., Andrejkovic, J. W., Bergauer, T., Chatterjee, S., Damanakis, K., … Zhokin, A. (2023). Probing small Bjorken-x nuclear gluonic structure via coherent J/ψ photoproduction in ultraperipheral Pb-Pb collisions at √s_NN=5.02 TeV. Physical Review Letters, 131(26), 262301 (22 pp.). https://doi.org/10.1103/PhysRevLett.131.262301

Persistent URL https://www.dora.lib4ri.ch/psi/islandora/object/psi:58500

Quasireal photons exchanged in relativistic heavy ion interactions are powerful probes of the gluonic structure of nuclei. The coherent J/ψ photoproduction cross section in ultraperipheral lead-lead collisions is measured as a function of photon-nucleus center-of-mass energies per nucleon (W^Pb_γN) over a wide range of 40<W^Pb_γN<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 W^Pb_γN, and plateau above W^Pb_γN≈40 GeV, up to 400 GeV, entering a new regime of small Bjorken-x (≈6×10⁻⁵) gluons being probed in a heavy nucleus. The observed energy dependence is not predicted by current quantum chromodynamic models.