Related papers: J/psi Spin Asymmetries in the Colour-Octet Model
We calculated the color-octet contribution to the double spin asymmetry of $J/\psi$ hadroproduction with nonzero transverse momenta at fixed target energies $\sqrt{s}\simeq40$ GeV. It is shown that the color-octet contribution is dominant…
At present the color-octet mechanism is still an important and debatable part in the non-relativistic QCD(NRQCD). We find in this work that the polarized double charmonium production at the LHC may pose a stringent test on the charmonium…
Charmonium production and absorption in heavy ion collisions is studied with the Ultrarelativisitic Quantum Molecular Dynamics model. We compare the scenario of universal and time independent color-octet dissociation cross sections with one…
We investigate $J/\psi$ production at a Photon Linear Collider (PLC) in the framework of NRQCD factorization approach. It was shown that color octet contribution is dominating in charmonium production at PLC. The main fraction of $J/\psi$…
We firstly examine hadroproduction of prompt J/psi's at the Fermilab Tevatron in a Monte Carlo Framework by means of the event generator PYTHIA 5.7 in which those colour-octet matrix elements processes relevant for charmonium production…
We investigate $J/\psi$ photoproduction asymmetries in the framework of the NRQCD factorization approach. It is shown that the color octet contribution leads to large uncertainties in the predicted asymmetries which rules out the…
We investigate $J/\psi$ photoproduction asymmetries in the framework of the NRQCD factorization approach. It is shown that the color octet contribution leads to large uncertainties in the predicted asymmetries which rules out the…
We give an overview of the present status of knowledge of the production of J/psi, psi' and Upsilon in high-energy hadron collisions. We first present two early models, namely the Colour-Singlet Model (CSM) and the Colour-Evaporation Model…
We discuss the double spin asymmetries in charmonium hadroproduction with nonzero transverse momenta at fixed target energies, $\sqrt{s}\simeq40$ GeV, within the framework of the factorization approach. It is shown that the color octet…
I discuss the impact of color-octet contributions to inclusive $J/\psi$ photoproduction at HERA. Emphasis is put on resolved photon processes and on $J/\psi$ polarization, which will be experimentally accessible at HERA in the near future.…
This thesis can be divided into several parts. The first one consists in a detailed historical review of quarkonium physics, centered on the different production models successively introduced. Then comes a review of the currently available…
We study the polarization observables of J/psi hadroproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics. We complete the present knowledge of the relativistic corrections by also…
We compute the decay rates and $H$-energy distributions of $B$ mesons into the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave charmonia, at next-to-leading order in the strong coupling. We find that a significant…
With the recent LHCb data on $\eta_c$ production and based on heavy quark spin symmetry, we obtain the long-distance matrix elements for both $\eta_c$ and $J/\psi$ productions, among which, the color-singlet one for $\eta_c$ is obtained…
Both charm and bottom quarks form nonrelativistic bound states analogous to positronium. The J/psi and psi(2S) charmonium states and the first three Upsilon(nS) bottomonium states, all spin-triplet S-wave quarkonium states below…
We studied the photoproduction of $\psi^{\prime}$ in the forward regions in polarized $\gamma p$ collisions at relevant HERA energies. We found that this reaction is very effective to test the color-octet mechanism which is based on the…
The cross section for the photoproduction of large-p_T J/psi mesons at HERA is calculated at next-to-leading order, adopting a perturbative approach to describe the fragmentation of charm quarks and gluons into J/psi mesons. We treat the…
We consider the production and decay of the $\chi_2$ charmonium state in polarized and unpolarized $pp$ collisions at RHIC in the framework of an effective theory based on the QCD multipole expansion. We find that the angular distribution…
Charmonia hadro- and photo-production are analyzed in the framework of the color-octet model taking into account higher-order effects induced by initial-state radiation of gluons. We argue that color-octet matrix elements obtained from…
Bound-state corrections to $J/\psi$ production from almost real photons are calculated in the colour-singlet model. A systematic, gauge-invariant, theory of hard quarkonium processes is used upto $O(v^2)$, where $v$ is the relative velocity…