| Autor: |
The GlueX Collaboration, Ali, A., Amaryan, M., Anassontzis, E. G., Austregesilo, A., Baalouch, M., Barbosa, F., Barlow, J., Barnes, A., Barriga, E., Beattie, T. D., Berdnikov, V. V., Black, T., Boeglin, W., Boer, M., Briscoe, W. J., Britton, T., Brooks, W. K., Cannon, B. E., Cao, N., Chudakov, E., Cole, S., Cortes, O., Crede, V., Dalton, M. M., Daniels, T., Deur, A., Dobbs, S., Dolgolenko, A., Dotel, R., Dugger, M., Dzhygadlo, R., Egiyan, H., Ernst, A., Eugenio, P., Fanelli, C., Fegan, S., Foda, A. M., Foote, J., Frye, J., Furletov, S., Gan, L., Gasparian, A., Gauzshtein, V., Gevorgyan, N., Gleason, C., Goetzen, K., Goncalves, A., Goryachev, V. S., Guo, L., Hakobyan, H., Hamdi, A., Han, S., Hardin, J., Huber, G. M., Hurley, A., Ireland, D. G., Ito, M. M., Jarvis, N. S., Jones, R. T., Kakoyan, V., Kalicy, G., Kamel, M., Kourkoumelis, C., Kuleshov, S., Kuznetsov, I., Larin, I., Lawrence, D., Lersch, D. I., Li, H., Li, W., Liu, B., Livingston, K., Lolos, G. J., Lyubovitskij, V., Mack, D., Marukyan, H., Matveev, V., McCaughan, M., McCracken, M., McGinley, W., McIntyre, J., Meyer, C. A., Miskimen, R., Mitchell, R. E., Mokaya, F., Nerling, F., Ng, L., Ostrovidov, A. I., Papandreou, Z., Patsyuk, M., Pauli, P., Pedroni, R., Pentchev, L., Peters, K. J., Phelps, W., Pooser, E., Qin, N., Reinhold, J., Ritchie, B. G., Robison, L., Romanov, D., Romero, C., Salgado, C., Schertz, A. M., Schumacher, R. A., Schwiening, J., Seth, K. K., Shen, X., Shepherd, M. R., Smith, E. S., Sober, D. I., Somov, A., Somov, S., Soto, O., Stevens, J. R., Strakovsky, I. I., Suresh, K., Tarasov, V., Taylor, S., Teymurazyan, A., Thiel, A., Vasileiadis, G., Werthmueller, D., Whitlatch, T., Wickramaarachchi, N., Williams, M., Xiao, T., Yang, Y., Zarling, J., Zhang, Z., Zhao, G., Zhou, Q., Zhou, X., Zihlmann, B. |
| Rok vydání: |
2019 |
| Předmět: |
|
| Zdroj: |
Physical review letters. 123(7) |
| ISSN: |
1079-7114
0031-9007 |
| Popis: |
We report on the measurement of the $\gamma p \rightarrow J/\psi p$ cross section from $E_\gamma = 11.8$ GeV down to the threshold at $8.2$ GeV using a tagged photon beam with the GlueX experiment. We find the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section $d\sigma /dt$ has an exponential slope of $1.67 \pm 0.39$ GeV$^{-2}$ at $10.7$ GeV average energy. The LHCb pentaquark candidates $P_c^+$ can be produced in the $s$-channel of this reaction. We see no evidence for them and set model-dependent upper limits on their branching fractions $\mathcal{B}(P_c^+ \rightarrow J/\psi p)$ and cross sections $\sigma(\gamma p \to P_c^+)\times\mathcal{B}(P_c^+ \to J/\psi p) $.
Comment: 12 pages, 7 figures |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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