Document Type
Article
Publication Date
5-4-1995
Abstract
This paper reports the cross section measurements for the process ep → e J/ψ p for Q2 < 4 GeV2 at s = 296 GeV, based on an integrated luminosity of about 0.5 pb-1, using the ZEUS detector. The J/ψ was detected in its e+e- and μ+μ- decay modes. The photoproduction cross section was measured to be 52-12+7 ± 10 nb at an average γp centre of mass energy of 67 GeV and 71-20+13±12 nb at 114 GeV. The significant rise of the cross section compared to lower energy measurements is not in agreement with VDM models, but can be described by QCD inspired models if a rise in the gluon momentum density at low x in the proton is assumed. © 1995.
Publication Source (Journal or Book title)
Physics Letters B
First Page
120
Last Page
134
Recommended Citation
Derrick, M., Krakauer, D., Magill, S., Mikunas, D., Musgrave, B., Repond, J., Stanek, R., Talaga, R., Zhang, H., Ayad, R., Bari, G., Basile, M., Bellagamba, L., Boscherini, D., Bruni, A., Bruni, G., Bruni, P., Cara Romeo, G., Castellini, G., Chiarini, M., Cifarelli, L., Cindolo, F., Contin, A., Corradi, M., Gialas, I., Giusti, P., Iacobucci, G., Laurenti, G., Levi, G., Margotti, A., Massam, T., Nania, R., & Nemoz, C. (1995). Measurement of the cross section for the reaction γp → J/ψ p with the ZEUS detector at HERA. Physics Letters B, 350 (1), 120-134. https://doi.org/10.1016/0370-2693(95)00403-8