Related papers: Coherence Effects in Diffractive Electroproduction…
We present a unified description of the vector meson and dilepton production in elementary and in heavy ion reactions. The production of vector mesons ($\rho,\omega$) is described via the excitation of nuclear resonances ($R$). The…
Photoproduction in ultra-peripheral relativistic heavy-ion collisions displays many unique features, often involving quantum mechanical coherence and two-source interference between photon emission from the two ions. We review the recent…
Dark photons serve as a portal to connect the dark and standard model sectors. Here, we propose photon-induced exclusive diffractive processes as a new tool to study the production of dark photons in current and future colliders. These…
Exclusive diffractive processes, such as exclusive vector meson production, serve as excellent probes of hadron structure within the perturbative regime of quantum chromodynamics (QCD). The exclusive process involving light and heavy vector…
We show that the double diffractive electroweak vector boson production in the $pp$ collisions at the LHC is an ideal probe of QCD based mechanisms of diffraction. Assuming the resolved Pomeron model with flavor symmetric parton…
High-energy vector meson photoproduction is an important tool for studying the partonic structure of matter at low Bjorken$-x$. In the Good-Walker (GW) paradigm, the cross-section $d\sigma/dt$ for coherent production of vector mesons or…
The differential cross section of coherent photo-production of heavy quarkonia on nuclear targets is calculated within the QCD color dipole formalism. The higher-twist nuclear shadowing corresponding to the $\bar QQ$ Fock component of the…
We study the dependence on photon virtuality $Q^2$ for the semihard quasi--elastic photoproduction of neutral vector mesons on a quark, gluon or real photon (at $s\gg p_{\bot}^2, Q^2; p_{\bot}^2 \gg \mu^2 \approx (0.3$ GeV)$^2$). To this…
The large $t$ behaviour of the helicity amplitudes of diffractive photoproduction is estimated relying on models of the photon and meson light-cone wave functions and on the double-logarithmic approximation to the exchanged gluon…
We explore the possibility of using ultra-peripheral proton-lead collisions at the LHC to study inclusive vector-quarkonium photoproduction, that occurs when a quasi-real photon emitted by a fully stripped lead ion breaks a proton to…
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…
The first measurement of coherent $\Upsilon$(1S) meson photoproduction off heavy nuclei is performed using ultraperipheral lead-lead collisions collected by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The…
Rho photoproduction on complex nuclei is re-examined using a generalised vector dominance model which succesfully predicts the observed nuclear shadowing in real photoabsorption and deep inelastic scattering. This model is shown to give a…
The next generation of $e^+e^-$ colliders will offer a possibility of clean testing of QCD dynamics. Recent progress in the theoretical description of exclusive processes permits for many of them a consistent use of the perturbative QCD…
Dielectrons probe a wide range of phenomena in heavy-ion collisions. These include light- and heavy-flavour meson production, thermal radiation and coherent photo-production. The latter process is distinguished by dielectron production at…
We demonstrate how the elementary amplitudes $\gamma N\to \Psi N$, the amplitude of the nondiagonal $J/\psi N\Leftrightarrow \psi' N$ transition, and the total $J/\psi N$ and $\psi' N$ cross sections can be determined from measurements of…
We calculate diffractive photo- and leptoproduction of $\rho$-, $\rho'$- and $\rho''$-mesons. The incoming photon dissociates into a $q\bar{q}$-dipole which scatters on the nucleon and transforms into a vector meson state. The scattering…
The diffractive process $\gamma p\to V + X$ (where $V$ is a vector meson and $X$ results from the dissociation of the proton) is studied. In particular, we consider the region of large momentum transfer (i.e. $|t|\gg\Lambda_{QCD}^2$) and…
In view of possible photoproduction studies in ultraperipheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of…
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,…