Related papers: Diffractive Electromagnetic Processes from a Regge…
The differential cross section for the process $\gamma \gamma \to \eta \pi^0$ has been measured in the kinematic range $0.84 \GeV < W < 4.0 \GeV$, $|\cos \theta^*|<0.8$, where $W$ and $\theta^*$ are the energy and $\pi^0$ (or $\eta$)…
Highlights selected from recent measurements of colour-singlet exchange processes at HERA are summarised. Particular emphasis is placed on energy and momentum transfer dependences and the decomposition of the data into an expansion in Regge…
In this paper we study the photon production in single and double diffractive processes considering the Resolved Pomeron model. We estimate the rapidity and transverse momentum dependence of the cross section for the diffractive double…
We extract the S-matrix element for dipole-proton scattering using the data on diffractive electroproduction of vector mesons at HERA. By considering the full t dependence of this process we are able to reliably unfold the profile of the…
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.…
Diffractive photoproduction of rho, phi and J/psi was studied in the BFKL approach to hard colour singlet exchange. Differential cross sections, the energy dependence and spin density matrix elements were calculated and compared to data…
Exclusive diffractive processes on the nucleon are investigated within a model in which the quark-nucleon interaction is mediated by Pomeron exchange and the quark substructure of mesons is described within a framework based on the…
A measurement is presented of dijet and 3-jet cross sections in low-|t| diffractive deep-inelastic scattering interactions of the type ep -> eXY, where the system X is separated by a large rapidity gap from a low-mass baryonic system Y.…
The production of $\phi$ mesons in the reaction $e^{+}p \rightarrow e^{+} \phi p$ ($\phi \rightarrow K^{+}K^{-}$) at a median $Q^{2}$ of $10^{-4} \ \rm{GeV^2}$ has been studied with the ZEUS detector at HERA. The differential $\phi$…
Production of electroweak bosons in e+e- annihilation into quarks and into leptons at energies much greater than 100 Gev is considered. We account for double-logarithmic contributions to all orders in electroweak couplings. It is assumed…
The diffractive electro- or photo-production of two mesons separated by a large rapidity gap gives access to generalized parton distributions (GPDs) in a very specific way. First, these reactions allow to easily access the chiral-odd…
Results on \jpsi production in $e p$ interactionsin the H1 experiment at HERA are presented. The \jpsi mesons are produced by almost real photons ($Q^2\approx 0$) and detected via their leptonic decays. The data have been taken in 1994 and…
A study is presented of the process gamma p -->XY, where there is a large rapidity gap between the systems X and Y. Measurements are made of the differential cross section as a function of the invariant mass mx of the system produced at the…
The total cross sections for the elastic electroproduction of $\rh0$ and $J/\Psi$ mesons for $Q^2$ $>$ 8 GeV$^2$ and $<W > \simeq 90$ GeV/c$^2$ are measured at HERA with the H1 detector. The measurements are for an integrated…
The unpolarized cross section for the electroproduction of the isoscalar $J^\pi = 3^+$ di-delta dibaryon $d^*$ is calculated for deuteron target using a simple picture of elastic electron-baryon scattering from the $\Delta \Delta (^7D_1)$…
Diffractive events are studied by means of identification of one or more rapidity gaps and/or a leading antiproton. Measurements of soft and hard diffractive processes have been performed at the Tevatron $p\bar p$ collider and presented. We…
The diffractive t-slope, B_V, of elastic charmonia (V=J/psi, psi') photo- and leptoproductions off a nucleon is studied at low |t| (< 1 GeV^2) in the leading logarithmic approximation of perturbative QCD, with a special emphasis on the…
Production of exclusive dijets in diffractive deep inelastic $e^\pm p$ scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 372 pb$^{-1}$. The measurement was performed for $\gamma^*-p$…
Recent measurements of diffractive vector-meson production with the general-purpose detectors H1 and ZEUS in electron-proton interactions with 300 GeV center-of-mass energy at the HERA accelerator complex have stimulated great interest in…
The empirical scaling law, wherein the total photoabsorption cross section depends on the single variable eta=(Q^2+m_0^2)/Lambda^2(W^2), provides empirical evidence for saturation in the sense of sigma_{gamma* p}(W^2,Q^2)/sigma_{gamma…