First Measurement of Near-Threshold J / ψ Exclusive Photoproduction off the Proton

Ali, A; Amaryan, M; Anassontzis, EG; Austregesilo, A; Baalouch, M; Barbosa, F; Barlow, J; Barnes, A; Barriga, E; Beattie, TD; Berdnikov, VV; Black, T; Boeglin, W; Boer, M; Briscoe, WJ; Britton, T; Brooks, WK; Cannon, BE; Cao, N; Chudakov, E; Cole, S; Cortes, O; Crede, V; Dalton, MM; 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, AM; Foote, J; Frye, J; Furletov, S; Gan, L; Gasparian, A; Gauzshtein, V; Gevorgyan, N; Gleason, C; Goetzen, K; Goncalves, A; Goryachev, VS; Guo, L; Hakobyan, H; Hamdi, A; Han, S; Hardin, J; Huber, GM; Hurley, A; Ireland, DG; Ito, MM; Jarvis, NS; Jones, RT; Kakoyan, V; Kalicy, G; Kamel, M; Kourkoumelis, C; Kuleshov, S; Kuznetsov, I; Larin, I; Lawrence, D; Lersch, DI; Li, H; Li, W; Liu, B; Livingston, K; Lolos, GJ; Lyubovitskij, V; Mack, D; Marukyan, H; Matveev, V; McCaughan, M; McCracken, M; McGinley, W; McIntyre, J; Meyer, CA; Miskimen, R; Mitchell, RE; Mokaya, F; Nerling, F; Ng, L; Ostrovidov, AI; Papandreou, Z; Patsyuk, M; Pauli, P; Pedroni, R; Pentchev, L; Peters, KJ; Phelps, W; Pooser, E; Qin, N; Reinhold, J; Ritchie, BG; Robison, L; Romanov, D; Romero, C; Salgado, C; Schertz, AM; Schumacher, RA; Schwiening, J; Seth, KK; Shen, X; Shepherd, MR; Smith, ES; Sober, DI; Somov, A; Somov, S; Soto, O; Stevens, JR; Strakovsky, II; Suresh, K; Tarasov, V; Taylor, S; Teymurazyan, A; Thiel, A; Vasileiadis, G; Werthmüller, D; Whitlatch, T; Wickramaarachchi, N; Williams, M; Xiao, T; Yang, Y; Zarling, J; Zhang, Z; Zhao, G; Zhou, Q; Zhou, X; Zihlmann, B

Author(s)

Fanelli, Cristiano; Hardin, John Melvin; Patsyuk, Maria; Williams, Michael; Yang, Y.

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Abstract

© 2019 American Physical Society. We report on the measurement of the γp→J/ψp cross section from Eγ=11.8 GeV down to the threshold at 8.2 GeV using a tagged photon beam with the GlueX experiment. We find that the total cross section falls toward the threshold less steeply than expected from two-gluon exchange models. The differential cross section dσ/dt has an exponential slope of 1.67±0.39 GeV-2 at 10.7 GeV average energy. The LHCb pentaquark candidates Pc+ 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 B(Pc+→J/ψp) and cross sections σ(γp→Pc+)×B(Pc+→J/ψp).

Date issued

2019

URI

https://hdl.handle.net/1721.1/133268.2

Department

Massachusetts Institute of Technology. Laboratory for Nuclear Science; Massachusetts Institute of Technology. Department of Physics

Journal

Physical Review Letters

Publisher

American Physical Society (APS)

Collections

MIT Open Access Articles

Version	Item	Date	Summary
2	1721.1/133268.2*	2022-09-06T20:20:37Z	Metadata changed: Verified or entered author name and department authority metadata.
1	1721.1/133268	2021-10-27T19:51:52Z

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