_version_ 1866912388553375744
author 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.
Gayoso, C. Ayerbe
Barlow, J.
Berdnikov, V. V.
Bhatt, H. D.
Bhetuwal, Deepak
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.
Zhou, X.
author_facet 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.
Gayoso, C. Ayerbe
Barlow, J.
Berdnikov, V. V.
Bhatt, H. D.
Bhetuwal, Deepak
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.
Zhou, X.
contents 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 $\sim8.2$ 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 $M(e^+e^-)\sim m_{J/ψ}=3.1$ 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 extracting a gluonic radius for bound protons of $\sqrt{\langle r^2\rangle}=0.85\pm0.14$ fm. The data also suggest an excess of the measured cross section for sub-threshold 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.
format Preprint
id arxiv_https___arxiv_org_abs_2409_18463
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle First Measurement of Near- and Sub-Threshold $J/ψ$ Photoproduction off Nuclei
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.
Gayoso, C. Ayerbe
Barlow, J.
Berdnikov, V. V.
Bhatt, H. D.
Bhetuwal, Deepak
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.
Zhou, X.
Nuclear Experiment
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 $\sim8.2$ 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 $M(e^+e^-)\sim m_{J/ψ}=3.1$ 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 extracting a gluonic radius for bound protons of $\sqrt{\langle r^2\rangle}=0.85\pm0.14$ fm. The data also suggest an excess of the measured cross section for sub-threshold 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.
title First Measurement of Near- and Sub-Threshold $J/ψ$ Photoproduction off Nuclei
topic Nuclear Experiment
url https://arxiv.org/abs/2409.18463