Related papers: Q Qbar g contribution to diffractive J/psi electro…
The near threshold photo or electroproduction of heavy vector quarkonium off the proton is studied in quantum chromodynamics. Similar to the high-energy limit, the production amplitude can be factorized in terms of gluonic Generalized…
We compute the contributions to large-$p_T$ $J/\psi$ production at HERA coming from fragmentation of gluons and charm quarks. We find that the charm quark fragmentation contribution dominates over the direct production of $J/\psi$ via…
We investigate the heavy quark photoproduction based on the k_T factorization approach, focusing on the results from the saturation model. The deviations in the results using the unintegrated gluon distribution considering the saturation…
We review the search for the quark-gluon plasma using the signal of the suppression of J/psi production in high-energy heavy-ion collisions. Recent observations of anomalous J/psi suppression in high-energy Pb-Pb collisions observed by 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…
The photoproduction reaction $\gamma N \to K K \Xi$ is investigated based on a relativistic meson-exchange model of hadronic interactions. The production amplitude is calculated in the tree-level approximation from relevant effective…
The comparison of $J/\psi$ photoproduction data in the inelastic region with theoretical predictions based on the NRQCD approach has remained somewhat ambiguous and controversial, in particular at large values of the inelasticity variable…
The photoproduction of the $J/\psi$ off the proton is believed to deepen our understanding of various physics issues. On the one hand, it is proposed to provide access to the origin of the proton mass, based on the QCD multipole expansion.…
In this paper we propose an approach in high energy QCD, which allows us to calculate the inclusive quarkonia production at ultra high energies. This approach is based on $t$-channel unitarity and on the expressions for dipole densities…
The recent data from H1 Collaboration on hadron multiplicity in diffractive DIS has been studied in the framework of perturbative QCD as a function of invariant diffractive mass. The formulas obtained explain the observed excess of particle…
Within the colour dipole picture for deep inelastic scattering at small Bjorken $x$, we study the production of a pair of relatively hard jets via coherent diffraction. By "relatively hard" we mean that the transverse momenta of the two…
The elastic leptoproduction of $\phi$ measured by the H1 collaboration at HERA is described by a perturbative QCD model, based on open $s\bar{s}$ production and parton hadron duality, proposed by Martin et al. We observe that both the total…
In this paper we study the production of energetic di-leptons. We calculate the rate for 2 $\to$ 2 processes. The log term is obtained analytically and the constant term is calculated numerically. When the photon mass is of the order of the…
Exclusive quarkonium photo- and electro-production off the nucleon is studied in the framework of generalized parton distributions (GPDs). The short distance part of the process is treated at leading order in perturbative Quantum…
The double coherent and non-coherent diffractive production of heavy quark - antiquark pairs ($Q \bar{Q}$) in heavy ion scattering at high energies (LHC) is considered. The total and differential cross sections of these processes with the…
Recently, a semiclassical approach to diffraction has been proposed, which treats the proton as a classical colour field. The present paper demonstrates that this approach is consistent with the concept of diffractive parton distributions.…
We evaluate the large momentum transfer $J/\psi$ photoproduction with rapidity gaps in ultraperipheral proton-ion collisions at the LHC which provides an effective method of probing dynamics of large t elastic hard QCD Pomeron interactions.…
We study prompt J/psi-meson hadroproduction invoking the hypothesis of gluon Reggeization in t-channel exchanges at high energy and the factorization formalism of nonrelativistic quantum chromodynamics at the leading order in the…
Using an effective Hamiltonian derived from the QCD multipole expansion, we calculate the cross sections of gluo-dissociation of heavy quarkonia in the quark-gluon plasma, by including both the chromo-electric dipole ($E_1$) as well as the…
The diffractive photoproduction of J/psi mesons is measured with the H1 detector at the ep collider HERA using an integrated luminosity of 78 pb^-1. The differential cross section d sigma(gamma p -> J/psi Y) / d t is studied in the range 2…