Observation of Coherent $\phi(1020)$ Meson Photoproduction in Ultraperipheral PbPb Collisions at $\sqrt{s_{NN}}$ = 5.36 TeV
Year: 2025
Type: article
Abstract: The first observation of coherent ϕ ( 1020 ) meson photoproduction off heavy nuclei is presented using ultraperipheral lead-lead collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The data were collected by the CMS experiment and correspond to an integrated luminosity of 1.62 μ b − 1 . The ϕ ( 1020 ) meson signals are reconstructed via the K + K − decay channel. The production cross section is presented as a function of the ϕ ( 1020 ) meson rapidity in the range 0.3 < | y | < 1.0 , probing gluons that carry a fraction of the nucleon momentum ( x ) around 10 − 4 . The observed cross section exhibits little dependence on rapidity and is significantly suppressed, by a factor of ∼ 5 , compared to a baseline model that treats a nucleus as a collection of free nucleons. Theoretical models that incorporate the nuclear shadowing effect generally provide a better description of the ϕ ( 1020 ) data than those incorporating gluon saturation. This study establishes a powerful new tool for exploring nuclear effects and nuclear gluonic structure in the small- x regime at a unique energy scale bridging the perturbative and nonperturbative quantum chromodynamics domains.
DOI: 10.5167/uzh-291797
Authors: Chekhovsky, V., Hayrapetyan, A., Makarenko, V., Tumasyan, A., Adam, W., Andrejkovic, J. W., Benato, L., Bergauer, T., Damanakis, K., Dragicevic, M., Giordano, C., Hussain, P. S., Jeitler, M., Krammer, N., Li, A., Liko, D., Mikulec, I., Schieck, J., Schöfbeck, R., Schwarz, D., Sonawane, M., Waltenberger, W., Wulz, C.-E., Janssen, T., Kwon, H., Van Laer, T., Van Mechelen, P., Breugelmans, N., D’Hondt, J., Dansana, S., CMS Collaboration, et al
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7130692562
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