{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.156185.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2899343"}},{"@id":"https://doi.org/10.1103/w9kp-f8xr","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"CMS Collaboration"},"creator":{"@type":"Organization","name":"CMS Collaboration"},"datePublished":"2025","description":"Incoherent J/$\u03c8$ photoproduction in heavy ion ultraperipheral collisions (UPCs) provides a sensitive probe of localized, fluctuating gluonic structures within heavy nuclei. This study reports the first measurement of the photon-nucleon center-of-mass energy ($W_{\u03b3\\mathrm{N}}$) dependence of this process in PbPb UPCs at a nucleon-nucleon center-of-mass energy of 5.02 TeV, using 1.52 nb$^{-1}$ of data recorded by the CMS experiment. The measurement covers a wide $W_{\u03b3\\mathrm{N}}$ range of $\\approx$ 40-400 GeV, probing gluons carrying a fraction $x$ of nucleon momentum down to an unexplored region of 6.5 $\\times$ 10$^{-5}$. Compared to baseline predictions neglecting nuclear effects, the measured cross sections exhibit significantly greater suppression at lower $x$. Additionally, the ratio of incoherent to coherent photoproduction is found to be constant across the probed $W_{\u03b3\\mathrm{N}}$ and $x$ range, disfavoring the establishment of the black disk limit. This study provides critical insights into the $x$-dependent evolution of fluctuating gluonic structures within nuclei and calls for further advancements in theoretical models incorporating nuclear shadowing and gluon saturation.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t1","@type":"Dataset","description":"The differential incoherent $\\mathrm{J}/\\psi$ photoproduction cross section as a function of $|y|$, in different neutron multiplicity classes.","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t2","@type":"Dataset","description":"The differential incoherent $\\mathrm{J}/\\psi$ photoproduction cross section as a function of $y$, in different neutron multiplicity classes.","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t3","@type":"Dataset","description":"The incoherent $\\mathrm{J}/\\psi$ photoproduction cross section as a function of photon-nuclear center-of-mass energy per nucleon $W_{\\gamma \\mathrm{N}}^{\\mathrm{Pb}}$ or Bjorken $x$,...","name":"Table 3"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t4","@type":"Dataset","description":"The nuclear suppression factor $S^{\\mathrm{J}/\\psi}$ of incoherent $\\mathrm{J}/\\psi$ meson photoproduction as a function of Bjorken $x$ in PbPb ultra-peripheral collisions...","name":"Table 4"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t5","@type":"Dataset","description":"The ratio between incoherent and coherent $\\mathrm{J}/\\psi$ meson photoproduction cross section as a function of photon-nuclear center-of-mass energy per nucleon...","name":"Table 5"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t6","@type":"Dataset","description":"The total covariance matrix of the total incoherent photoproduction cross section as a function of photon-nuclear center-of-mass energy per nucleon...","name":"Total covariance matrix"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t7","@type":"Dataset","description":"The experimental covariance matrix of the total incoherent photoproduction cross section as a function of photon-nuclear center-of-mass energy per nucleon...","name":"Experimental covariance matrix"},{"@id":"https://doi.org/10.17182/hepdata.156185.v1/t8","@type":"Dataset","description":"The theoretical (photon flux) covariance matrix of the total incoherent photoproduction cross section as a function of photon-nuclear center-of-mass energy...","name":"Theoretical covariance matrix"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2899343?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/156185"}],"inLanguage":"en","name":"Small-$x$ evolution of gluon fields from incoherent J/$\\psi$ photoproduction in ultraperipheral PbPb collisions","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2899343?version=1","version":1}