Markus Diehl
(DESY)
18/04/2007, 14:00
Joint: DIFF / SPIN
I present a detailed study of exclusive meson production at large Q^2 in
terms of generalized parton distributions, focusing at the effect of the
NLO corrections to the hard scattering. Numerical investigations are
performed for the kinematic regions of various experiments (from HERA
collider to JLAB energies). I comment on the stability of the
perturbative expansion in collinear...
Simonetta Liuti
(University of Virginia)
18/04/2007, 14:20
Joint: DIFF / SPIN
We propose a physically motivated parametrization for the unpolarized Generalized Parton Distributions (GPDs), H and E, valid at both zero and non-zero values of the skewness variable, zeta. We start from a detailed study of the zeta = 0 case where H and E are determined using constraints from simultaneous fits of experimental data on both the nucleon elastic form factors and the deep...
Armine Rostomyan
(DESY)
18/04/2007, 15:00
Joint: DIFF / SPIN
Hard exclusive meson production in deep inelastic lepton scattering provides access to the unknown Generalized Parton Distributions (GPDs) of the nucleon. GPDs parameterize the nucleon structure and provide a unified description of exclusive and inclusive reactions.
Predictions based on a GPD model have shown that the transverse target spin asymmetry of exclusive $\rho^0$ mesons is sensitive...
Andreas Metz
(Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum)
18/04/2007, 15:20
Joint: DIFF / SPIN
Recent work suggests a close relation between generalized and transverse momentum dependent parton distributions (TMDs), in particular for the so-called naive time-reversal odd TMDs. In the talk our present knowledge on this topic will be briefly summarized. Moreover, an extension of the existing work in the literature will be discussed.
Hayg Guler
(DESY)
18/04/2007, 16:10
Joint: DIFF / SPIN
For the first time, azimuthal beam-spin asymmetries have been measured in electroproduction of a hard exclusive photon on nuclei ranging from Deuterium to Xenon. The data were accumulated by the HERMES experiment at HERA/DESY in the years 1996-2004 by scattering the 27.6 GeV lepton beam off an internal gas target. The asymmetries of the coherent and incoherent processes for D, 4He, N, Ne, Kr...
88.
HERMES measurement of DVCS from p and d targets, and status and prospects of the recoil detector
Andreas Mussgiller
(University of Erlangen)
18/04/2007, 16:30
Joint: DIFF / SPIN
Hard exclusive processes provide access to the unknown generalized parton distributions (GPDs), which extend our description of the nucleon structure beyond the standard parton distributions. The Deeply Virtual Compton Scattering (DVCS) process, i.e. the hard exclusive leptoproduction of real photons, provides the theoretically cleanest access to the GPDs. DVCS amplitudes can be measured most...
Eric Voutier
(LPSC / Université Joseph Fourier)
18/04/2007, 16:55
Joint: DIFF / SPIN
I would like to bring your attention on the Hall A exprimental program about GPDs at JLab. Two experiments have been recently performed investigating GPDs via the DVCS reaction off the proton and off the neutron. They involve the HRS spectrometer for the detection of the scattered electron and a new PbF2 calorimeter for the detection of the emitted photon. The latter was specially designed...
Josh Pierce
(University of Virginia)
18/04/2007, 17:20
Joint: DIFF / SPIN
The eg1b run was conducted using CLAS (CEBAF Large Acceptance Spectrometer) at the Thomas Jeㄦson National Accelerator Facility (TJNAF) in 2000 by the CLAS collaboration. A 1.6 GeV - 5.6 GeV polarized electron beam and polarized nuclear targets (composed of NH3 and ND3) were used, allowing single and double spin asymmetries to be measured.
This analysis is of the double spin asymmetry Ajj in...
