Related papers: The Color Evaporation Model in Diffractive $J/\psi…
The H1 Collaboration recently reported a new analysis on the inelastic photo- production of J/\psi mesons at DESY HERA ep collider. We show that these new experimental results are well described by the Color Evaporation Model for quarkonium…
The diffractive photoproduction of vector mesons is usually described considering the two-gluon (Pomeron) exchange, non-diagonal parton distributions and the contribution of the real part to the cross section. In this letter we analyze the…
We assess the theoretical uncertainties on the inclusive J/psi production cross section in the Color Evaporation Model (CEM) using values for the charm quark mass, renormalization and factorization scales obtained from a fit to the charm…
The DELPHI Collaboration has recently reported the measurement of J/Psi production in photon-photon collisions at LEP II. These newly available data provide an additional proof of the importance of colored c bar{c} pairs for the production…
The color evaporation model simply states that charmonium production is described by the same dynamics as $D \bar D$ production, {\em i.e.}, by the formation of a colored $c \bar c$ pair. Its color happens to be bleached by soft final-state…
Photoproduction of $J/\psi$ is considered including the color-octet contributions from the various partial wave states, $^{2S+1}L_J$ = $^1S_0$, $^3S_1$ and $^3P_J$. The production cross section depends on three new nonperturbative…
We use a new approach to color evaporation model (CEM) for quarkonium production. The production of $c\bar c$ pairs is performed within $k_T$-factorization approach using different unintegrated gluon distribution functions (UGDF) from the…
We use a new approach to color evaporation model (CEM) for quarkonium production. The production of $c\bar c$ pairs is performed within $k_T$-factorization approach using different unintegrated gluon distribution functions (UGDF) from the…
We estimate the differential and total cross sections for both the photoproduction of vector D*-meson and its yield in deep inelastic scattering at the HERA collider in the framework of model motivated by perturbative calculations in QCD.…
I compute the leading color-octet contributions to the process $\gamma + p \to J/\psi + \gamma (+ X)$ within the non-relativistic QCD (NRQCD) factorization formalism. In the color-singlet model, $J/\psi + \gamma$ can only be produced when…
We study J/psi photoproduction via fragmentation at next-to-leading order in the QCD-improved parton model, using the nonrelativistic factorization formalism proposed by Bodwin, Braaten, and Lepage. We consider direct and resolved…
We calculate the production of J/psi mesons by neutrino-nucleon collisions in fixed target experiments. Soft color, often referred to as color evaporation effects, enhance production cross sections due to the contribution of color octet…
Based on the color-singlet model, we investigate the photoproduction of $J/\psi$ associated with a $c \bar{c}$ pair with all subprocesses including the direct, single-resolved, and double-resolved channels. The amplitude squared of these…
We use the color-octet mechanism combined with the two gluon exchange model for the diffractive $J/\psi$ production in resolved photon processes. In the leading logarithmic approximation in QCD, we find that the diffractive $J/\psi$…
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…
In the article, we study associated production of prompt $J/\psi(\Upsilon)$ and $D-$mesons in the improved color evaporation model using the high-energy factorization approach as it is realized in the Monte-Carlo event generator KaTie. The…
We propose the color-octet mechanism combined with the two gluon exchange model for the diffractive $J/\psi$ production in hadron collisions. In the leading logarithmic approximation (LLA) in QCD, we find that the diffractive $J/\psi$…
In the article, the study of unpolarized $J/\psi$ production in proton-proton collisions is presented. The Soft Gluon Resummation approach as a TMD framework was used for description of small-$p_T^{}$ production cross section. The Improved…
Measurements by the Belle Collaboration of the cross section for inclusive J/psi production in e^+e^- annihilation have been a serious challenge to current heavy-quarkonium theory. Especially, the measured cross sections for exclusive…
Inelastic and diffractive production of J/psi mesons at HERA is reviewed. The data on inelastic photoproduction are described well within errors by the Colour Singlet Model in next-to-leading order. A search for colour octet processes…