205 research outputs found
Spin Effects and Amplitude Structure in Vector Meson Photoproduction at Small
An analysis of light vector meson photoproduction at small on the basis
of the generalized parton distribution (GPD) approach is presented. Our results
on the cross section and spin density matrix elements (SDME) are in fair
agreement with DESY experiments. The predicted double spin longitudinal
asymmetry is not small at HERMES energies.Comment: LateX file (use wrapfile.sty), 4 figures, report at the XI Workshop
on High Energy Spin Physics, Dubna, Russia, September 27 - October 1, 200
GPDs and spin effects in light mesons production
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
asymmetry for various reactions are presented.Comment: 8 pages, 14 figs, report at the Advanced Studies Institute Symmetries
And Spin (SPIN-Praha-2009) Prague, July 26 - August 2, 200
Polarized GPDs in pions and kaons electroproduction. Tranversity effects
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 description of experimental data. Our results on the cross section are in
agreement with experiment. We present our predictions for spin observables.Comment: 8 pages, 12 figures, talk at the International Conference "Advanced
Studies Institute Symmetries And Spin" (SPIN-Praha-2012) Prague, July 1 - 8,
201
Diffractive hadron leptoproduction and SPD
We discuss diffractive hadron leptoproduction in terms of skewed gluon
distributions and within two-gluon exchange model. Connection of the two-gluon
approach with skewed gluon distributions is found. The double spin asymmetries
for longitudinally polarized leptons and transversely polarized protons in
diffractive vector meson and production at high energies within the
two-gluon model is analysed.
The asymmetry predicted for meson production is found to be quite small. The
asymmetry for production is large and can be used to obtain
information on the polarized skewed gluon distributions in the proton.Comment: 16 pages, latex, 9 figures, lectures presented at the Conference
"Symmetries and Spin" - Praha-SPIN-2002, Prague, July 14 - 27, 200
Spin Asymmetries In Proton-Proton Scattering At High Energies And Moderately Large Momentum Transfer
We study scattering at high energies and moderately large momentum
transfer using a QCD--based model in which the proton is viewed as being
composed of a quark and a diquark. This model leads to spin asymmetries which
are neither small nor vanish at high energies. The predicted ratio of helicity
flip and non-flip amplitudes is about 0.2-0.3 and asymmetry is about
20-30% for .Comment: Latex, 3 pages, 2 figures, uses sprocl.sty. Talk at SPIN98 symposium,
September 8-12, Protvino, Russi
Large - Distance Effects in QCD and Spin Asymmetries in Diffractive Reactions
Large - distance effects in the hadron wave function for the hadron-Pomeron
vertex in the QCD -model are discussed. It is shown that they lead to the
spin-flip part of the Pomeron coupling which can reach with
respect to the non-flip part. The obtained structure of the Pomeron coupling
modifies spin asymmetries in high--energy diffractive reactions where the
Pomeron structure becomes determinative. We study spin asymmetries in exclusive
reactions and in the diffractive and production. We have
found that spin effects in these diffractive processes are sensitive to the
spin-flip part of the Pomeron coupling.Comment: Report at the XIV International Seminar On High Energy Physics
Problems "RELATIVISTIC NUCLEAR PHYSICS AND QUANTUM CHROMODYNAMICS" Dubna,
August 17-22, 199
Double spin asymmetry in diffractive production at SMC energies and quark-pomeron vertex structure
It is shown that the longitudinal double spin asymmetry in polarized
diffractive reaction depends strongly on the spin
structure of quark-pomeron vertex. The SMC spin facilities may be one of the
best place to perform such experiment.Comment: 5 pages, Latex, 3 figures are appended at the end (as uufile
Diffractive hadron production and pomeron coupling structure
Large-distance effects, which lead to the spin-flip part of the hadron
-pomeron coupling in QCD -models, are discussed. We study spin asymmetries in
exclusive reactions and in diffractive and vector meson production
which are sensitive to the spin-dependent part of the pomeron coupling.Comment: 6 pages, latex, 4 figures, to be published in Proc. of the
International Bogolyubov Conference "Problems of Theoretical and Mathematical
Physics", September 27- October 6, Moscow-Dubna-Kyi
Transversity effects in light meson leptoproduction
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),
and are essential in the description of spin effects in the
pseudoscalar and vector meson leptoproduction.Comment: 6 pages, 9 figures, talk at the SPIN-Praha-2013 conference, Prague,
July 7 - 13, 201
Cross sections and spin asymmetries in vector meson leptoproduction
Light vector meson leptoproduction is analyzed on the basis of the
generalized parton distributions. Our results on the cross section and spin
effects are in good agrement with experiment at HERA, COMPASS and HERMES
energies. Predictions for asymmetry for various reactions are
presented.Comment: 4 pages, 6 figures, report in XIII Workshop On High Energy Spin
Physics, Dubna, Russia September 1 - 5, 200
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