Related papers: Vector Mesons and DVCS at HERA
Recent measurement of inclusive processes and hadronic final states in diffractive deep-inelastic scattering at HERA are used to investigate the QCD factorisation properties and study partonic structure of colour singlet exchange. Resolved…
The cross section for ep -> e b\bar{b} X in photoproduction is measured with the H1 detector at the ep-collider HERA. The decay channel b\bar{b} -> ee X' is selected by identifying the semi-electronic decays of the b-quarks. The total…
The diffractive scattering of photon off proton $\gamma^{(*)} p \to \gamma Y$ (where $Y$ denotes the proton dissociative system or the elastically scattered proton) is measured in two different kinematic regimes at high energy with the H1…
A very wide body of HERA diffractive electroproduction data is confronted with the predictions of the colour dipole model. In doing so we focus upon three different parameterisations of the dipole scattering cross-section, whose parameters…
By using a Regge-pole model for vector meson production (VMP), successfully describing the HERA data, we analyse the correlation between VMP cross sections in photon-induced reactions at HERA and those in ultra-peripheral collisions at the…
Recent experimental results on inclusive diffractive scattering and on exclusive vector meson production are reviewed. The dynamical picture of hard diffraction emerging in perturbative QCD is highlighted.
Heavy-flavoured jets have been studied in photoproduction at HERA. This includes the first measurement of dijet angular distributions in D* photoproduction and the ratio of the vector/(vector + pseudoscalar) production rate for charm…
Jet photoproduction, where the two highest transverse energy ($\ETJ$) jets have $\ETJ$ above 6 GeV and a jet-jet invariant mass above 23~GeV, has been studied with the ZEUS detector at the HERA $ep$ collider. Resolved and direct…
Since the start of HERA operation there has been considerable progress in the understanding of jet production in e p collisions. QCD calculations are now able to accommodate the hadronic structure of the virtual photon. The luminosities…
We estimate the differential and total cross sections for both the photoproduction of vector D*-meson and its yield in deep inelastic scattering at the HERA collider in the framework of model motivated by perturbative calculations in QCD.…
Dijet production by almost real photons has been studied at HERA with the ZEUS detector. Jets have been identified using the cone algorithm. A cut on xg, the fraction of the photon energy participating in the production of the two jets of…
The production of dijets in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of $61 \pbi$. The dijet cross section has been measured for virtualities of the exchanged…
The exclusive deep inelastic electroproduction of $\psi(2S)$ and $J/\psi(1S)$ at an $ep$ centre-of-mass energy of 317 GeV has been studied with the ZEUS detector at HERA in the kinematic range $2 < Q^2 < 80$ GeV$^2$, $30 < W < 210$ GeV and…
It is shown that the universality of the initial and final state interactions responsible for the transition between the on-- and off--mass shell states leads to the energy independence of the ratio of exclusive $\rho$ electroproduction…
A measurement is presented of elastic Deeply Virtual Compton Scattering e^+ + p -> e^+ + photon + p at HERA using data taken with the H1 detector. The cross section is measured as a function of the photon virtuality, Q^2, and the invariant…
It is demonstrated that the "soft pomeron" (together with a secondary reggeon) describing cross-sections of hadron-hadron collisions is fairly able to describe the energy dependence of cross-sections of exclusive (virtual) photoproduction…
The production of heavy quarks has been studied in photoproduction processes with the ZEUS detector at HERA using an integrated luminosity of $36.9 pb^{-1}$. Events with a photon virtuality, $Q^2<1 GeV^2$, were selected with two jets of…
The electromagnetic radiative correction to the cross section of the vector meson electroproduction is calculated. Explicit covariant formulae for the observed cross section are obtained. The dependence of the radiative correction on the…
The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma^* p -> X p, in e^+p collisions at HERA. The data cover photon virtualities in two ranges, 0.03<Q^2<0.60 GeV^2 and 2<Q^2<100…
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…