Probing the hidden-bottom pentaquark resonances in photonuclear bottomonium production near threshold: Differential observables

We study the near-threshold (sic)(1S) meson photoproduction from protons and nuclei by considering incoherent direct non-resonant (gamma p -> (sic)(1S)p, gamma n -> (sic)(1S)n) and two-step resonant (gamma p +P-bt(+) -> (sic)(1S)p, gamma n -> P-bt(0) -> (sic)(1S)n, i = 1, 2, 3; P-b1(+,0) = P-b(+,0)(11080), P-b2(+,0) = P-b(+,0) (11125), P-b3(+,0) = P-b(+,0)(11130)) bottomonium production processes with the main goal of clarifying the possibility to observe the non-strange hidden-bottom pentaquark states P-bt(+,0) in this production via differential observables. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of (sic)(1S) mesons on protons, on carbon and tungsten target nuclei at near-threshold incident photon beam energies by assuming the spin-parity assignments of the hypothetical hidden-bottom resonances P-b(+,0) (11080), P-b(+,0) (11125) and P-b(+,0) (11130) as JP = (1/2)-, JP = (1/2)- and JP = (3/2)- within four different realistic choices for the branching ratios of their decays to the (sic)(1S)p and (sic)(1S)n modes (0.125, 0.25, 0.5 and 1%) as well as for two options for the background contribution. We demonstrate that the measurements of these combined observables on proton and nuclear targets in the near-threshold energy region in future experiments at the planned high-luminosity electron-ion colliders EIC and EicC in the US and China should provide evidence for the existence of the above hidden-bottom pentaquark resonances as well as clarify their decay rates.

Automated summary

In this study, we investigate the near-threshold meson photoproduction from protons and nuclei and explore the possibility of observing non-strange hidden-bottom pentaquark states through differential observables. We calculate the excitation functions and energy/momentum distributions for different production processes and propose that future experiments at high-luminosity electron-ion colliders could provide evidence for the existence of these hidden-bottom pentaquark resonances.