Document Type
Article
Publication Date
2025
DOI
10.1103/PhysRevLett.134.201903
Publication Title
Physical Review Letters
Volume
134
Issue
20
Pages
201903 (1-8)
Abstract
We report on the first measurement of J/ψ photoproduction from nuclei in the photon energy range of 7 to 10.8 GeV, extending above and below the photoproduction threshold in the free proton of ∼8.2 GeV. The experiment used a tagged photon beam incident on deuterium, helium, and carbon, and the GlueX detector at Jefferson Lab to measure the semi-inclusive A(γ,e+e-p) reaction with a dilepton invariant mass M(e+e-)∼mJ/ψ=3.1 GeV. The incoherent J/ψ photoproduction cross sections in the measured nuclei are extracted as a function of the incident photon energy, momentum transfer, and proton-reconstructed missing light-cone momentum fraction. Comparisons with theoretical predictions assuming a dipole form factor allow for extracting a gluonic radius for bound protons of «r2» = 0.85±0.14 fm. The data also suggest an excess of the measured cross section for subthreshold production and for interactions with high missing light-cone momentum fraction protons. The measured enhancement can be explained by modified gluon structure for high-virtuality bound protons.
Rights
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Original Publication Citation
Pybus, J. R., Ehinger, L., Kolar, T., Devkota, B., Sharp, P., Yu, B., Dalton, M. M., Dutta, D., Gao, H., Hen, O., Piasetzky, E., Santiesteban, S. N., Schmidt, A., Somov, A., Szumila-Vance, H., Adhikari, S., Asaturyan, A., Austregesilo, A., Ayerbe Gayoso, C.,…Zhou, X. (2025). First measurement of near-threshold and subthreshold J/ψ photoproduction off nuclei. Physical Review Letters, 134(20), 1-8, Article 201903. https://doi.org/10.1103/PhysRevLett.134.201903
ORCID
0000-0001-9288-8008 (Adhikari)
Repository Citation
Pybus, J. R.; Ehinger, L.; Kolar, T.; Devkota, B.; Sharp, P.; Yu, B.; Dalton, M. M.; Dutta, D.; Gao, H.; Hen, O.; Piasetzky, E.; Santiesteban, S. N.; Schmidt, A.; Somov, A.; Szumila-Vance, H.; Adhikari, S.; Asaturyan, A.; Austregesilo, A.; Ayerbe Gayoso, C.; Barlow, J.; Berdnikov, V. V.; Bhatt, H. D.; Bhetuwal, D.; Black, T.; Briscoe, W. J.; Chung, G.; Cole, P. L.; Deur, A.; Dotel, R.; Egiyan, H.; Eugenio, P.; Fanelli, C.; Gan, L.; Gasparian, A.; Guo, J.; Hernandez, K.; Higinbotham, D. W.; Hurck, P.; Jaegle, I.; Jones, R. T.; Kakoyan, V.; Karki, A.; Li, H.; Li, W. B.; Linera, G. R.; Lyubovitskij, V.; Marukyan, H.; McCaughan, M. D.; McCracken, M.; Mizutani, K.; Nguyen, D.; Oresic, S.; Ostrovidov, A. I.; Papandreou, Z.; Paudel, C.; Peters, K.; Ritman, J.; Schick, A.; Schwiening, J.; Smith, A.; Somov, S.; Strakovsky, I.; Suresh, K.; Tarasov, V. V.; Taylor, S.; Xiao, T.; Zhang, Z.; and Zhou, X., "First Measurement of Near-Threshold and Subthreshold J/ѱ Photoproduction Off Nuclei" (2025). Physics Faculty Publications. 968.
https://digitalcommons.odu.edu/physics_fac_pubs/968
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