The possibility to study in-medium modification of $J/\psi$ mesons from their photoproduction on nuclei near threshold in the case of presence of the LHCb pentaquark states $P_c^{+}$ in this photoproduction

Abstract

We study the $J/\psi$ photoproduction from nuclei in the near-threshold beam energy region of $E_{\gamma }$=5--11 GeV within the nuclear spectral function approach by considering incoherent direct ($\gamma N\to J/\psi N$) and two-step ($\gamma p\to P_c^{+}(4312)$, $P_c^{+}(4312)\to J/\psi p$; $\gamma p\to P_c^{+}(4440)$, $P_c^{+}(4440)\to J/\psi p$; $\gamma p\to P_c^{+}(4457)$, $P_c^{+}(4457)\to J/\psi p$) $J/\psi$ production processes. We calculate the absolute excitation functions for the non-resonant and resonant production of $J/\psi$ mesons off ${}^{12}$C and ${}^{208}$Pb target nuclei within the different scenarios for in-medium modification of the directly photoproduced $J/\psi$ mesons and for branching ratios of the decays $P_c^{+}(4312)\to J/\psi p$, $P_c^{+}(4440)\to J/\psi p$ and $P_c^{+}(4457)\to J/\psi p$. We show that the non-resonant subthreshold $J/\psi$ production in $\gamma A$ reactions reveals some sensitivity to employed in-medium modification scenarios for $J/\psi$ mesons, which is not masked by the resonantly produced $J/\psi$ mesons, only if above branching ratios are less than 5\%. We also demonstrate that if these branching ratios more than 5\% then the presence of the $P_c^{+}(4312)$, $P_c^{+}(4440)$ and $P_c^{+}(4457)$ resonances in $J/\psi$ photoproduction on nuclei produces above threshold additional enhancements in the behavior of the total $J/\psi$ creation cross section on nuclei, which could be also studied in the future JLab experiments at the CEBAF facility to provide both further evidence for their existence and valuable information on their nature.

14 pages

References in corpus (10)

• Big-Bang Nucleosynthesis
• Observation of a narrow pentaquark state, $P_c(4312{)}^{+}$, and of two-peak structure of the $P_c(4450{)}^{+}$
• Emergence of a complete heavy-quark spin symmetry multiplet: seven molecular pentaquarks in light of the latest LHCb analysis
• Strong LHCb evidence supporting the existence of the hidden-charm molecular pentaquarks
• Heavy quark spin symmetric molecular states from ${\bar{D}}^{(\ast )}{\Sigma }_c^{(\ast )}$ and other coupled channels in the light of the recent LHCb pentaquarks
• Isospin breaking decays as a diagnosis of the hadronic molecular structure of the $P_c(4457)$
• Studying the P_c(4450) resonance in J/psi photoproduction off protons
• Possibility to study pentaquark states $P_c(4312),P_c(4440)$, and $P_c(4457)$ in $\gamma p\to J/\psi p$ reaction
• Heavy quark spin multiplet structure of $P_c(4312)$, $P_c(4440)$, and $P_c(4457)$
• The GlueX Experiment: Recent Results and Future Plans

Cited by in corpus (6)

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• Probing the hidden-bottom pentaquark resonances in photonuclear bottomonium production near threshold: differential observables
• Towards clarifying the possibility of observation of the LHCb hidden-charm pentaquarks $P_c^{+}(4312)$, $P_c^{+}(4337)$, $P_c^{+}(4440)$ and $P_c^{+}(4457)$ in near-threshold charmonium photoproduction off protons and nuclei
• Absorption of $\psi (2S)$ mesons in nuclei
• Absorption of 1$P$-wave heavy charmonium ${\chi }_{c1}(1P)$ in nuclei