Related papers: Coherent Photoproduction from Nuclei
We study the photoproduction of vector mesons off proton and off nuclear targets. We work within the colour dipole model in an approach that includes subnucleon degrees of freedom, so-called hot spots, whose positions in the…
We argue that with an increase of the collision energy, elastic photoproduction of $\rho$ mesons on nuclei becomes affected by the significant cross section of photon inelastic diffraction into large masses, which results in the sizable…
Study of color transparency (CT) effects at moderate energies is more problematic than is usually supposed. Onset of CT can be imitated by other mechanisms, which contain no explicit QCD dynamics. In the case of the $(e,e'p)$ reaction the…
We review the phenomenon of color coherence in quantum chromodynamics (QCD), its implications for hard and soft processes with nuclei, and its experimental manifestations. The relation of factorization theorems in QCD with color coherence…
CONTENTS. 1.Introduction, 1.1 QCD ideas to be tested; 2. Coherence phenomena in QED, 2.1 Charge transparency, 2.2 Charge filtering, 2.3 Charge opacity; 3. Color transparency in perturbative QCD, 3.1 Coherence length in QCD, 3.2 Bjorken…
We calculate cross sections and transverse momentum distributions for the incoherent diffractive production of vector mesons $J/\psi$ and $\Upsilon$ on heavy nuclei. In distinction to coherent diffraction, the nucleus is allowed to break…
Hard diffractive photo- and electroproduction of heavy vector mesons ($J/\psi$ and $\Upsilon$) is evaluated within the leading $\alpha_s\ln{Q^2 \over\Lambda_{QCD}^2}$ approximation of QCD. In difference from our earlier work on that…
In a previous publication, we have presented a model for the photoproduction of $\mathrm{J/}\psi$ vector mesons off protons, where the proton structure in the impact-parameter plane is described by an energy-dependent hot-spot profile. Here…
The exclusive $\Upsilon$ photoproduction in proton-proton and proton - nucleus collisions at LHC energies is investigated using the color dipole formalism and considering different models for the $\Upsilon$ wave function and forward dipole…
We report the first measurement at the LHC of coherent photoproduction of $\rho^0$ mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for $\rho^0$ production are studied in the $\pi^+…
The energy-dependent hotspot model is used to predict cross sections for vector-meson diffractive photo-nuclear production off oxygen ($\gamma$O) and neon ($\gamma$Ne) that can be extracted from ultra-peripheral O--O and Ne--Ne collisions,…
We evaluate the cross sections for the production of vector mesons in exclusive ultraperipheral proton-ion collisions at LHC. We find that the rates are high enough to study the energy and momentum transfer dependence of vector mesons -…
The invariant-mass distribution for the coherent photoproduction of dipions in ultraperipheral PbPb collisions is measured using data, corresponding to an integrated luminosity of $224.6 \pm 9.6 \mu$b$^{-1}$, collected by the LHCb…
Quantum mechanics is central to coherent photoproduction in ultra-peripheral collisions (UPCs). This writeup will discuss some surprising aspects of UPCs that stem from these quantum mechanical roots. The Good-Walker (GW) paradigm, which…
High energy multiparticle photoproduction off nuclear targets is studied. The photon is assumed to interact in direct scattering processes or as a resolved $q\bar{q}$-state according to the Generalized Vector Dominance Model. In the…
Using the Gribov-Glauber model for photon-nucleus scattering and a generalization of the vector meson dominance model for the hadronic structure of the photon, we make predictions for the cross section of incoherent $\rho$ photoproduction…
Heavy ion collisions are rich and complex systems that involve different aspects of QCD and electromagnetic phenomena. From head-on collisions to the case in which the nuclei miss each other, many of QCD and photo-induced probes are being…
Heavy nuclei at collider energies are a source of high energy Weizsaecker-Williams photons. This photon flux may be utilized to study high energy photon-nucleus interactions. Here we concentrate on the coherent diffractive production of…
Exclusive coherent and incoherent electroproduction of the $\rho^0$ meson from $^1$H and $^{14}$N targets has been studied at the HERMES experiment as a function of coherence length ($l_c$), corresponding to the lifetime of hadronic…
I discuss issues related to charmonium production, in view of physics possibilities at a 15 ... 30 GeV continuous beam electron facility. High energy photo- and hadroproduction of heavy quarkonia presents several challenges to QCD models…