1. Measurement of $J/\psi$ and $\psi\left(2S\right)$ production in $p+p$ and $p+d$ interactions at 120 GeV
- Author
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Leung, C. H., Nagai, K., Nakano, K., Nawarathne, D., Dove, J., Prasad, S., Wuerfel, N., Aidala, C. A., Arrington, J., Ayuso, C., Barker, C. L., Brown, C. N., Chang, W. C., Chen, A., Christian, D. C., Dannowitz, B. P., Daugherity, M., Fassi, L. El, Geesaman, D. F., Gilman, R., Goto, Y., Guo, R., Hague, T. J., Holt, R. J., Hossain, M. F., Isenhower, D., Kinney, E., Klein, A., Kleinjan, D. W., Kudo, Y., Lin, P. -J., Liu, K., Liu, M. X., Lorenzon, W., McClellan, R. E., McGaughey, P. L., Medeiros, M. M., Miyachi, Y., Miyasaka, S., Morton, D. H., Nakahara, K., Nara, S., Pate, S. F., Peng, J. C., Pun, A., Ramson, B. J., Reimer, P. E., Rubin, J. G., Sanftl, F., Sawada, S., Sawada, T., Scott, M. B. C., Shibata, T. -A., Tadepalli, A. S., Teo, M., Towell, R. S., Uemura, S., Wang, S. G., Wickes, A. B., Wu, J., and Ye, Z. H.
- Subjects
High Energy Physics - Experiment ,Nuclear Experiment - Abstract
We report the $p+p$ and $p+d$ differential cross sections measured in the SeaQuest experiment for $J/\psi$ and $\psi\left(2S\right)$ production at 120 GeV beam energy covering the forward $x$-Feynman ($x_F$) range of $0.5 < x_F <0.9$. 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 $\sigma_{\psi\left(2S\right)} / \sigma_{J/\psi}$ cross section ratios are found to increase as $x_F$ increases, indicating that the $q \bar{q}$ annihilation process has larger contributions in the $\psi\left(2S\right)$ production than the $J/\psi$ production. The $\sigma_{pd}/2\sigma_{pp}$ cross section ratios are observed to be significantly different for the Drell-Yan process and $J/\psi$ production, reflecting their different production mechanisms. We find that the $\sigma_{pd}/2\sigma_{pp}$ ratios for $J/\psi$ production at the forward $x_F$ region are sensitive to the $\bar{d}/ \bar{u}$ flavor asymmetry of the proton sea, analogous to the Drell-Yan process. The transverse momentum ($p_T$) distributions for $J/\psi$ and $\psi\left(2S\right)$ production are also presented and compared with data collected at higher center-of-mass energies., Comment: 8 pages, 7 figures
- Published
- 2024