Measurement of J/ψ and ψ(2S) production in p + p and p + d interactions at 120 GeV

oleh: C.H. Leung, K. Nagai, K. Nakano, D. Nawarathne, J. Dove, S. Prasad, N. Wuerfel, C.A. Aidala, J. Arrington, C. Ayuso, C.L. Barker, C.N. Brown, W.C. Chang, A. Chen, D.C. Christian, B.P. Dannowitz, M. Daugherity, L. El Fassi, D.F. Geesaman, R. Gilman, Y. Goto, R. Guo, T.J. Hague, R.J. Holt, M.F. Hossain, D. Isenhower, E. Kinney, A. Klein, D.W. Kleinjan, Y. Kudo, P.-J. Lin, K. Liu, M.X. Liu, W. Lorenzon, R.E. McClellan, P.L. McGaughey, M.M. Medeiros, Y. Miyachi, S. Miyasaka, D.H. Morton, K. Nakahara, S. Nara, S.F. Pate, J.C. Peng, A. Pun, B.J. Ramson, P.E. Reimer, J.G. Rubin, F. Sanftl, S. Sawada, T. Sawada, M.B.C. Scott, T.-A. Shibata, A.S. Tadepalli, M. Teo, R.S. Towell, S. Uemura, S.G. Wang, A.B. Wickes, J. Wu, Z.H. Ye

Format: Article
Diterbitkan: Elsevier 2024-11-01

Deskripsi

We report the p+p and p+d differential cross sections measured in the SeaQuest experiment for J/ψ and ψ(2S) production at Image 1 beam energy covering the forward x-Feynman (xF) range of 0.5<xF<0.9. The measured cross sections are in good agreement with theoretical calculations based on the nonrelativistic QCD (NRQCD) using the long-distance matrix elements deduced from a recent global analysis of proton- and pion-induced charmonium production data. The σψ(2S)/σJ/ψ cross section ratios are found to increase as xF increases, indicating that the qq¯ annihilation process has larger contributions in the ψ(2S) production than the J/ψ production. The σpd/2σpp cross section ratios are observed to be significantly different for the Drell-Yan process and J/ψ production, reflecting their different production mechanisms. We find that the σpd/2σpp ratios for J/ψ production at the forward xF region are sensitive to the d¯/u¯ flavor asymmetry of the proton sea, analogous to the Drell-Yan process. The transverse momentum (pT) distributions for J/ψ and ψ(2S) production are also presented and compared with data collected at higher center-of-mass energies.