Hard exclusive reactions and generalized parton distributions

Avetik Hayrapetyan; I. Brodski; M. Dueren; E. Etzelmueller; M. Stahl; H. Stenzel

doi:10.1051/epjconf/20159504029

EPJ

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Proceedings

Open Access

EPJ Web of Conferences 95, 04029 (2015)
https://doi.org/10.1051/epjconf/20159504029

Hard exclusive reactions and generalized parton distributions

Avetik Hayrapetyan^a, I. Brodski, M. Dueren, E. Etzelmueller, M. Stahl and H. Stenzel on behalf of the HERMES Collaboration^b

Justus-Liebig University, Giessen, Germany

^a e-mail: Avetik.Hayrapetyan@uni-giessen.de
^b http://hermes.desy.de/

Published online: 29 May 2015

Abstract

The recently developed formalism of Generalized Parton Distributions (GPDs) allows connecting the experimental information of hard exclusive reactions to the spin contribution and even to the angular momentum contribution of quarks in the nucleon. By selecting different quantum numbers of the final state in exclusive productions, different GPDs can be addressed separately. The HERMES experiment at the HERA ring at DESY (Hamburg) made pioneering contributions and first constraints to Generalized Parton Distributions (GPDs), using hard exclusive vector meson production (EVMP) and Deeply Virtual Compton Scattering (DVCS). Using a novel recoil detector, HERMES managed to measure DVCS and EVMP free of any significant background. Selected results are highlighted and discussed in this paper.

© Owned by the authors, published by EDP Sciences, 2015

This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.