Speaker
Description
In this contribution, we study the inclusive and diffractive $\eta_{c}$ photoproduction in $pp$ and $pPb$ ultra-peripheral collisions (UPC's) at the LHC Run II energies. In a hadron-hadron UPC, is well known that the hadrons can act as sources of almost real photons allowing the study of photon-photon and photon-hadron interactions. Our goal is the study of the $\eta_{c}$ production in photon-gluon and the photon-Pomeron subprocesses using the nonrelativistic QCD formalism (NRQCD). In this formalism, the photon-hadron process can be factorized in terms of the short distances coefficients for the photon-gluon subprocess (perturbatively calculated) and long distances matrix elements, related to the formation of the quarkonium at the final state, which are extracted from global analysis of the quarkonium data. As the photoproduction of $\eta_{c}$ is a purely color – octet contribution, this process is a probe of the color – octet mechanism. In our analysis, we show our predictions for the rapidity and $p_{T}$ distributions and total cross sections for the $\eta_{c}$ photoproduction. A comparison with the predictions for the $\eta_{c}$ production in photon-photon and exclusive photon-hadron interactions is presented.
