相关论文: Color-Dipole Picture versus Hard Pomeron in Deep I…
In this paper, we study fully differential quarkonia photoproduction observables in ultraperipheral collisions (UPCs) as functions of momentum transfer squared. We employ the dipole picture of the QCD part of the scattering with proton and…
A model based on a dipole Pomeron framework for vector meson exclusive photoproduction by real and virtual photons shows very good agreement with the experimental data. The model does not violate unitarity constrains and describes in a…
We study photon--meson transition form factors $\gamma^*(Q^2)\gamma \to \pi^0,\eta,\eta'$ at low and moderately high virtualities $Q^2$ of one of the photons, the second photon being real. For the description of the form factor at low…
The diffractive dissociation of a hadron at high energies, by either Coulomb or Pomeron exchange, has a natural description in QCD as the materialization of the projectile's light-cone wavefunctions; in particular, the diffractive…
High precision measurements of the form factors of proton, pion, and kaon for timelike momentum transfers of |Q^2|=s=14.2 and 17.4 GeV^2 have been made. Data taken with the CLEO-c detector at sqrt(s)=3.772 GeV and 4.170 GeV, with integrated…
Coherent photoproduction of heavy quarkonia on nuclear targets is studied within the QCD color dipole formalism including several main phenomena: i) The correlation between impact parameter of a collision $\vec b$ and dipole orientation…
We have performed precision measurements of the double-spin virtual-photon asymmetry $A_1$ on the neutron in the deep inelastic scattering regime, using an open-geometry, large-acceptance spectrometer. Our data cover a wide kinematic range…
A Reggeometric (Regge+Geometry) model, based on the observed proportionality between the forward slope of the differential cross section and the interaction radius, the latter depending on virtuality Q2 of the incoming virtual photon and on…
The scaling in $\sigma_{\gamma^*p}$ cross sections (for $Q^2/W^2 << 1$) in terms of the scaling variable $\eta = (Q^2 + m^2_0)/\Lambda^2 (W^2)$ is interpreted in the generalized vector dominance/color-dipole picture (GVD/CDP). The quantity…
We present a study of Ioffe times in deep inelastic electron-proton scattering. We deduce 'experimental' Ioffe-time distributions from the small-x HERA data as described by a particular colour-dipole-model fit. We show distributions for…
Drell-Yan dilepton pair production and inclusive direct photon production can be described within a unified framework in the color dipole approach. The inclusion of non-perturbative primordial transverse momenta and DGLAP evolution is…
The Real Compton Scattering in ultraperipheral $pPb$ collisions at RHIC and LHC energies is investigated and predictions for the squared transverse momentum ($t$) and rapidity ($Y$) distributions are presented. The scattering amplitude is…
We explore the consequences for diffractive production, gamma* p --> X p, in deep inelastic scattering at low values of x\sim Q^2/W^2 <<1 that follow from our recent representation of the total photoabsorption cross section, sigma_{gamma*…
We argue that study of the cross section of coherent photo(electro) production of $\rho,\rho^{\prime}, ...$-mesons provides an effective method to probe onset of black body limit(BBL) in the soft and hard QCD interactions. We illustrate the…
Hadron colliders offer a unique opportunity to test perturbative QCD because, rather than producing events at a specific beam energy, the dynamics of the hard scattering is probed simultaneously at a wide range of momentum transfers. This…
The matrix element squared for Compton scattering of a heavy photon on a longitudinally polarized electron is calculated. The gauge-invariant tensor structure of the heavy photon polarization is considered, assuming that all kinematical…
The generalized parton distributions (GPDs) have emerged as a universal tool to describe hadrons in terms of their elementary constituents, the quarks and the gluons. Deeply virtual Compton scattering (DVCS) on a proton or neutron ($N$), $e…
In this work the double vector meson production in two-photon interactions at high energies is investigated considering saturation physics. We extend the color dipole picture for this process and study the energy and virtuality dependence…
The strikingly different high energy behaviours of real photoabsorption cross-sections with Q^2 = 0 and the low x proton structure function at large Q^2 are studied from a laboratory frame viewpoint, in which the x and Q^2 dependence…
Based on the vector meson dominance assumption, a Hamiltonian model has been developed to investigate $J/\Psi$ photo-production reaction on the nucleon by using the $J/\Psi$-nucleon potential extracted from a lattice QCD calculation of…