Münster 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
HK: Fachverband Physik der Hadronen und Kerne
HK 12: Hadronenstruktur und -spektroskopie IV
HK 12.5: Vortrag
Montag, 21. März 2011, 17:45–18:00, HS3
Hard exclusive vector-meson leptoproduction — •Mayya Golembiovskaya — DESY
The HERMES experiment at DESY, Hamburg collected a set of data on hard exclusive vector meson leptoproduction using the 27.6 GeV longitudinally polarized lepton/positron beam of the HERA accelerator and longitudinally or transversely polarized as well as unpolarized gas targets. Measurements of exclusive vector-meson production give possibility to study nucleon structure since the process can be described in terms of Generalized Parton Distributions (GPDs). Spin-density matrix elements (SDMEs) describe the final vector-meson spin state. Ratios of helicity amplitudes, connected with different SDMEs and various interaction types, are presented for ρ0 production. A confirmation of contribution from unnatural-parity-exchange amplitudes are obtained from the analysis of these amplitude ratios. A deviation from the hypothesis of s-channel helicity conservation is observed, whereas results for φ production are in agreement with this hypothesis. Comparisons of experimental results with GPD model predictions are also presented.