Related papers: Spin effects in hard exclusive electroproduction o…
In this talk various spin effects in hard exclusive electroproduction of mesons are briefly reviewed and the data discussed in the light of recent theoretical calculations within the frame work of the handbag approach. For electroproduction…
Light meson electroproduction is analyzed on the basis of the handbag approach. Our results on the cross section and spin effects are in good agrement with experiments at HERA, COMPASS and HERMES energies. Predictions for $A_{UT}$ asymmetry…
We analyze light meson electroproduction within the handbag model. We study cross sections and spin asymmetries for various mesons. The essential role of the transversity $\tilde H_T$ and $\tilde E_T$ GPDs in electroproduction of…
I review recent theory developments for hard exclusive and semi-exclusive production of mesons, emphasising the variety of physics issues that can be studied in these processes.
Hard exclusive pi+ electroproduction is investigated within the handbag approach. The prominent role of the pion-pole contribution is demonstrated. It is also shown that the experimental data require a twist-3 effect which ensues from the…
We analyze the electroproduction of pseudoscalar mesons within the handbag approach. To investigate these reactions, we consider the leading-twist contribution together with the transversity twist-3 effects that are crucial in the…
We analyze light meson electroproduction in the intermediate energy range where the quark contributions are essential. Our calculations are carried out on the basis of the handbag approach. We study cross sections and spin asymmetries for…
In this talk it is reported on an analysis of hard exclusive electroproduction of pseudoscalar mesons within the handbag approach. It is argued that recent measurements of pion electroproduction performed by HERMES and CLAS clearly indicate…
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…
In this talk it is reported on an analysis of hard exclusive pion electroproduction within the handbag approach. Particular emphasis is laid on single-spin asymmetries. It is argued that a recent HERMES measurement of asymmetries measured…
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…
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 light meson electroproduction is analyzed within the handbag approach. We consider the leading-twist contribution together with the transversity effects. We show that the transversity Generalized Parton Distributions (GPDs), $H_T$ and…
We explore the feasibility to study exclusive meson production (EMP) in hard muon-proton scattering at the COMPASS experiment. These measurements constrain the off-forward parton distributions (OFPD's) of the proton, which are related to…
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…
Spin effects in high energy fragmentation processes can provide us with important information on hadronization mechanisms and spin structure of hadrons. It can in particular give new tests to the hadronization models. In this talk, we make…
The spin and flavor symmetries of the heavy quark effective theory are employed to discuss the exclusive cross sections for pair production of heavy mesons in photon-photon collision. The ratios of the exclusive cross sections for heavy…
The present status of applications of perturbative QCD to large momentum transfer exclusive reactions is discussed. It is argued that in the region of momentum transfer accessible to present day experiments soft contributions dominate the…
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 reported on an analysis of Phi-meson electroproduction at small Bjorken-x within the handbag approach. The amplitudes factorize into generalized parton distributions and a partonic subprocess, electroproduction off gluons. Cross…