Related papers: Hard Meson Electroproduction And Twist-3 Effects
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…
The cross section of the exclusive $\pi^0$ and $\eta$ electroproduction reaction $ep\to e^\prime p^\prime \pi^0/\eta$ was measured at Jefferson Lab with a 5.75-GeV electron beam and the CLAS detector. Differential cross sections…
We show how deeply virtual pseudoscalar meson production experiments single out the contribution of the four chiral odd quark-proton GPDs which are related to the so far elusive transversity distribution function, $h_1$. Furthermore, in the…
Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and…
We discuss the relevance of studying single transverse-spin asymmetry in hard-exclusive meson electroproduction in the backward region. Such an asymmetry could help us discriminate between contributions from a soft baryon exchange in the…
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…
The exclusive $\pi^0$ electroproduction is analyzed within the handbag approach based on Generalized Parton Distributions (GPDs) factorization. We consider the leading-twist contribution together with the transversity effects. It is shown…
Wide-angle photoproduction of pseudoscalar mesons is investigated under the assumption of dominance of the handbag mechanism considering both quark helicity flip and non-flip. The partonic subprocess, meson photoproduction off quarks, is…
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…
It is reported on an analysis of electroproduction of light mesons at small Bjorken-x within the handbag approach. The partonic subprocesses, meson electroproduction off quarks or gluons, are calculated within the modified perturbative…
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 discuss the recent data of exclusive $\pi^0$ (and $\pi^+$) electroproduction on the proton obtained by the CLAS collaboration at Jefferson Lab. It is observed that the cross sections, which have been decomposed in $\sigma_T…
We consider the pion pole contribution and transversity effects determined by the $H_T$ and $\bar E_T$ Generalized Parton Distributions (GPDs) which are essential in hard pseudoscalar and vector meson leptoproduction. We investigate spin…
A general analysis of polarization phenomena for coherent meson electroproduction on deuterons, $e+ d\to e+ d +P^0$, where $P^0$ is a pseudoscalar $\pi ^0$ or $\eta$-meson, is presented. The spin structure of the electromagnetic current for…
Exclusive production of $\omega$ mesons was studied at the COMPASS experiment by scattering $160~\mathrm{GeV}/\mathit{c}$ muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured…
The twist-3 contribution, consisting of twist-2 transversity generalized parton distributions (GPDs) and a twist-3 meson wave function, to deeply virtual pion electroproduction is discussed. The twist-3 meson wave function includes both the…
The amplitude for hard exclusive pseudoscalar meson electroproduction off nucleon (nuclear) targets is computed in QCD within the leading $\alpha_s \ln {Q^2/\lambda_{QCD}^{2}}$ approximation. We show that the distribution of recoil nucleons…
We consider hard electroproduction of mesons at twist-3 level and focus our attention on helicity flip amplitudes corresponding to the production of transversely polarized mesons by transverse photons. We demonstrate that helicity-flip…
We study light vector meson electroproduction at small $x$ within the generalized parton distributions (GPDs) model. The modified perturbative approach is used, where the quark transverse degrees of freedom in the vector meson wave function…
Electroproduction of two vector mesons with a large rapidity gap between them provides the first feasible selective access to chiral-odd GPDs. The scattering amplitude of the process $ \gamma ^* N \to \rho_L^0 \rho_T^+ N'$ may be…