Threshold J/ψ Photoproduction with GlueX at Jefferson Lab
- Thomas Jefferson National Accelerator Facility, Newport News, VA 23606, U.S.A.
We report preliminary results for the $$\gamma p \rightarrow J/\psi p$$ exclusive cross-section from the threshold up to a photon energy of $12$ GeV. These measurements have a direct relation to the pentaquarks, $$P^+_c(4380)$$ and $$P^+_c(4450)$$, reported by LHCb, expected to be seen in the $$s$$-channel photoproduction $$\gamma p \rightarrow P_c \rightarrow J/\psi p$$, allowing to put a limit on the $$P^+_c(4450) \rightarrow J/\psi p$$ branching ratio. The near threshold production mechanism is discussed, as well. The GlueX experiment uses a tagged-photon beam produced by electrons from the 12 GeV CEBAF machine. The detector system is based on a 2 T solenoid and includes electro-magnetic calorimeters and drift chambers providing full acceptance coverage. The $$J/\psi $$ particles are registered by their decay into $e^+e^-$ pairs identified in the calorimeters. Taking advantage of the exclusivity of the reaction and the precise knowledge of the beam energy, we achieve a high mass resolution and a very low background, allowing us to perform a more sensitive unbinned analysis.
- Research Organization:
- Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP)
- DOE Contract Number:
- AC05-06OR23177
- OSTI ID:
- 1975851
- Report Number(s):
- JLAB-PHY-19-2883; DOE/OR/23177-6269
- Journal Information:
- Proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), Conference: Proceedings of the 8th International Conference on Quarks and Nuclear Physics (QNP2018), Tsukuba, Japan, November 13, 2018
- Country of Publication:
- United States
- Language:
- English
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