${\overline{D}}^0$-meson photoproduction off the proton is studied at energies from the process threshold up to 20 GeV. The background part of the process is modeled within the Regge model with the help of ${\overline{D}}^0$-meson trajectories that are being exchanged in the $t$ channel or ${\mathrm{\Lambda }}_c^{+}$-baryon trajectories exchanged in the $u$ channel. These contributions create cross sections which are smooth functions of energy. The introduction of exchanges of three hidden-charm pentaquarks with spin $1/2$ and $3/2$ in the $s$ channel then creates sharp peaks in the cross section predictions. In order to account for the finite size of the particles involved, we introduce hadron form factors. In analysis of model predictions with pseudoscalar and pseudovector couplings in the strong vertex, the contact term was shown to play a non-negligible role. A great merit of the proposed approach is its limited number of parameters that need to be adjusted as there are to this date no data available for this process. Being limited by the broken SU(4) symmetry and guided by other works that show their predictions of this process, we could adjust the parameters manually in order to provide at least qualitative results.

• Received 14 July 2020
• Accepted 10 September 2020

DOI:https://doi.org/10.1103/PhysRevD.102.074009