Related papers: GPDs and spin effects in light mesons production
In this talk it is reported on an analysis of hard exclusive leptoproduction of pions within the handbag approach. It is argued that recent measurements of this process performed by HERMES and CLAS clearly indicate the occurrence of strong…
Estimates for electroproduction of pseudoscalar mesons at small values of skewness are presented. Cross sections and asymmetries for these processes are calculated within the handbag approach which is based on factorization in hard parton…
It is reported on a global analysis of hard vector-meson electroproduction which is based on the handbag factorization. The generalized parton distributions are constructed from their forward limits with the help of double distributions and…
It is reported on an analysis of vector meson electroproduction at small Bjorken-x within the handbag approach. Using a model for the generalized parton distribution and calculating the partonic subprocess, electroproduction off gluons,…
Recent measurements, in particular those on $\Lambda$ polarization and spin alignment of vector mesons in $e^+e^-$ annihilation at LEP, and those on the azimuthal asymmetry at HERA, have attracted much attention on the spin effects in high…
It is shown that the $A_{ll}$ asymmetry in diffractive $Q \bar Q$ leptoproduction is not small at HERA energies and dependent on the structure of the pomeron couplings and on the masses of produced quarks. The connection of this asymmetry…
We present a status report on a study of vector meson leptoproduction for the HERA energy range on the basis of the generalized handbag approach. In contrast to the leading twist approach transverse degrees of freedom as well as Sudakov…
The target asymmetry for electroproduction of vector mesons is investigated within the handbag approach. While the generalized parton distribution (GPD) H is taken from a previous analysis of the elctroproduction cross section, we here…
A successful interpretation of the cross sections for elastic and inelastic vector meson production can be made if one assumes the underlying dynamics to be governed by hard partonic subprocesses. Extending these partonic approaches to…
Hard exclusive electroproduction of $\omega$ mesons is studied with the HERMES spectrometer at the DESY laboratory by scattering 27.6 GeV positron and electron beams off a transversely polarized hydrogen target. The amplitudes of five…
We investigate exclusive electroproduction of vector and pseudoscalar mesons at large photon virtuality $Q^2$. These reactions were analyzed within the handbag approach where amplitudes factorize into hard subprocesses and generalized…
The electroproduction of rho mesons is studied at HERA with the H1 detector at high Q^2 and high |t|. Cross sections are measured as a function of Q^2, W and t. The W dependence of the gamma*-p cross section is observed to increase with Q^2…
We analyze electroproduction of light vector mesons (V=rho, phi and omega) at small Bjorken-x in the handbag approach in which the process factorizes into general parton distributions and partonic subprocesses. The latter are calculated in…
The exclusive $\eta$ and $\pi^0$ electroproduction is studied in the handbag approach based on Generalized Parton Distributions (GPDs) factorization. Predictions of $\pi^0$ and $\eta$ mesons are calculated for future Electron-Ion Collider…
We investigate exclusive leptoproduction of $\rho^0$ meson. These reactions were analyzed within the factorizing handbag approach. In our model good agreement of observables for light meson production with experimental data in a wide energy…
We study light hadron leptoproduction at small $x$. Vector meson production is analysed in terms of generalized gluon distributions with taking into account the transverse quark motion. Within a two-gluon model the double spin asymmetries…
The energy dependence of the cross section for exclusive electroproduction of vector mesons is discussed as a way to learn about the interplay of soft and hard interactions. The question of determining the scale of these processes is…
We study light vector meson photoproduction at small $x$ on the basis of the generalized parton distribution (GPD). Our results on the cross section and spin density matrix elements (SDME) are in fair agreement with DESY experiments
At the electron-proton collider HERA the inclusive $D^{*\pm}$ meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions. For the first, where $<W_{\gamma p}>…
Results on elastic vector meson production at HERA are presented in the framework of perturbative QCD. The energy dependence of the cross section for J/Psi photoproduction and for rho electroproduction is studied. A full polarisation…