Related papers: Extracting the rho meson wavefunction from HERA da…
The elastic production of vector mesons at HERA is discussed from the theoretical point of view. We briefly review different models, their successes and shortcomings. Main emphasis is put on recent issues in perturbative QCD calculations.…
We show that photoproduction cross sections recently measured by ZEUS and H-1 at HERA energies$^1$ are in agreement with our earlier prediction based on high-energy hadronic structure of the photon in the QCD minijet-type model$^2$. We…
The diffraction dissociation of virtual photons is considered in the framework of conventional Regge theory. It is shown that the recent HERA data on large rapidity gap events can be successfully described in terms of the Pomeron structure…
We present results from recent investigations of diffractive vector meson production using the ZEUS detector at HERA. These consist of measurements of rho production in the region of photon virtuality 0.25 < Q^2 < 0.85 GeV^2, of rho, phi,…
We determine the mass spectroscopy and light-front wave functions (LFWFs) of the $\rho$-meson by solving the holographic Schr\"odinger equation of light-front chiral QCD along with the 't Hooft equation of (1+1)-dimensional QCD in the large…
We show that the recent measurements of the total photoproduction cross section at HERA energies [1] are in agreement with our earlier prediction based on high-energy hadronic structure of the photon in the QCD minijet-type model [2]. We…
We predict the cross-section for diffractive $\phi$ electroproduction within the dipole model, using a holographic meson wavefunction for the $\phi$. For the dipole cross-section, we use the Color Glass Condensate dipole model whose…
Production and decay angular distributions were extracted from measurements of exclusive electroproduction of the rho^0(770) meson over a range in the virtual photon negative four-momentum squared 0.5< Q^2 <4 GeV^2 and the photon-nucleon…
Predictions for the diffractive photoproduction of the $\Upsilon$-family at HERA energies, within the framework of the analysis by Frankfurt, Koepf and Strikman, are presented. Two novel effects lead to a significant enhancement of the…
We compute pseudorapidity and transverse momentum distributions for charm and bottom production at HERA. We examine the effect of next-to-leading order QCD corrections, the effect of possible intrinsic transverse momenta of the incoming…
We confront saturation-based results for diffractive $\psi(2s)$ and $\rho$ production at HERA and $J/\psi$ photoproduction with all available data including recent ones from HERA, ALICE and LHCb, finding a good agreement. We show that the…
We summarise recent progress in the computation of helicity amplitudes for diffractive vector meson production at large momentum transfer and their comparison to data collected at the HERA collider.
Exclusive processes in hard electroproduction is one of the best place for understanding the factorization properties of QCD. The HERA experiment recently provided precise data for rho electroproduction, including all spin density matrix…
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…
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…
Diffractive dissociation of particles can be used to study their light-cone wave function. Results from Fermilab experiment E791 for diffractive dissociation of 500 GeV/c $\pi^-$ mesons into di-jets are presented. The results show that the…
A review of light-cone, covariant and gauge-invariant wave-functions of mesons is presented. They are basic non-perturbative objects needed for hard exclusive processes and for the method of light-cone QCD sum rules. The emphasis is on the…
We present a review of the latest exclusive diffraction results achieved at HERA, discussing in particular the $W$ and $t$ dependence of the measured cross-sections in both DIS and photo-production regimes.
The cross section for the elastic photoproduction of \r0 mesons ($\gamma p \to \rho^0 p$) has been measured with the H1 detector at HERA for two average photon-proton centre-of-mass energies of 55 and 187 GeV. TheFcenterline lower energy…
We compute a light front wave function for heavy vector mesons based on long distance matrix elements constrained by decay width analyses in the Non Relativistic QCD framework. Our approach provides a systematic expansion of the wave…