| CMS Physics Analysis Summaries | |
| Report number | CMS-PAS-HIN-23-009 |
| Title | The Bjorken-x evolution of fluctuating gluon fields probed via incoherent J/psi photoproduction in PbPb collisions at sqrt(sNN) = 5.02 TeV |
| CMS Collaboration | |
| CMS Collaboration | |
| Nuclear Physics - Experiment | |
| CERN LHC ;CMS | |
| The cross section for incoherent $\rm J/\psi$ photoproduction off lead nuclei is measured to probe the event-by-event fluctuations of the gluon field density within heavy nuclei across a broad range of Bjorken-$x$. Results are obtained using PbPb ultraperipheral collisions at a 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 dependence of the cross section on the photon-nucleus center-of-mass energy per nucleon $W_{\gamma\rm N}^{\rm Pb}$ is studied from $W_{\gamma\rm N}^{\rm Pb} \approx 40$ GeV up to 400 GeV, corresponding to a Bjorken-$x$ interval of $5.8 \times 10^{-3} > x > 6.5\times 10^{-5}$. The ratio of incoherent to coherent $\rm J/\psi$ cross sections is found to be independent of $W_{\gamma\rm N}^{\rm Pb}$ and $x$ over the range studied. Significant nuclear suppression of incoherent $\rm J/\psi$ photoproduction is observed.For $x < 10^{-4}$, the suppression is comparable to that observed in coherent $\rm J/\psi$ photoproduction, becoming more pronounced as $x$ increases. | |
| Inspire | |
| superseded by:CERN-EP-2025-030 | |
Email contact:cms-pag-conveners-heavyions@cern.ch         Fulltext in PDF Figure_002 Figure_005-b Figure_005-a Figure_004 Figure_003 Figure_001-b Figure_001-a Additional information for the analysis (restricted access) | |
Record created 2024-09-22, last modified 2025-03-12
PDF