The production mechanisms of open strangeness (K * ) and open charm (D * ) vector mesons in π − p scattering, namely, π − + p → K * 0 + Λ and π − + p → D * − + Λ + c , are investigated within the modified quark-gluon string model. In order to identify the major reaction mechanisms, we consider the subsequent decays of the produced vector mesons into two pseudoscalar mesons, i.e., K * → K + π and D * → D + π. We found that the decay distributions and density matrix elements are sensitive to the production mechanisms and can be used to disentangle the vector trajectory and pseudoscalar trajectory exchange models. Our results for K * production are compared with the currently available experimental data and the predictions for D * production processes are presented as well. Our predictions can be tested at the present or planned experimental facilities.

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We investigate the reaction mechanism of the φ-meson photoproduction off the proton target, i.e., γp → φp, up to √ s = 2.8 GeV. For this purpose, we employ an effective Lagrangian approach in the tree-level Born approximation, and we employ various experimental and theoretical inputs. As a theoretical setup, the vectorlike Pomeron (C = +1) is taken into account as a parameterized two-gluon exchange contribution. We also consider f1(1285) axial-vector-meson, (π, η) pseudoscalarmeson, and (a0, f0) scalar-meson exchanges in the t channel, in addition to the experimentally confirmed nucleon resonances, such as N * (2000, 5/2 + ) and N * (2300, 1/2 + ), for the direct φ-meson radiations in the s and u channels. We provide numerical results for the total and differential cross sections as well as the spin-density matrices in the Gottfried-Jackson, Adair, and helicity frames. We observe that, together with the universally accepted pomeron contribution, the considered meson and nucleon-resonance contributions play significant roles in reproducing the experimental data for the forward and backward φ-meson scattering-angle regions, respectively, indicating the nontrivial interferences between mesonic and baryonic contributions.

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