Two-gluon production of φ and η′ mesons in proton-proton collisions at high energies

We discuss gluon-gluon mechanisms for production of mesons with hidden strangeness, such as eta' and phi meson, in proton-proton collisions at large energies. The g* g* -> eta' and g*g* -> phi g mechanisms are considered only, and the corresponding cross sections are calculated in the k(t)-factorization approach. The F-gamma*gamma*->eta' and F-g*g*->eta' form factors are calculated from the quark-antiquark eta' light-cone wave function including quark/antiquark transverse momenta. The result for the two-photon transition form factor demonstrates that higher twists may survive even to large photon virtualities. The result is compared with the result of a recent leading-twist next-to-leading-order analysis, which uses phenomenological distribution amplitudes fitted to exclusive production of eta' in e(+)e(-) -> e(+)e(-)eta' reaction. We calculate transverse momentum distributions of both eta' and phi mesons in proton-proton collisions for Relativistic Heavy Ion Collider and LHC energies. The results are compared to experimental data whenever available. The results of the Lund string model are shown for comparison for eta' production at LHC energies. It seems that the two-gluon fusion is not the dominant mechanism for both phi and eta' production, although the situation for eta', especially at larger energies, is less clear due to lack of experimental data.