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HK: Physik der Hadronen und Kerne
HK 9: Poster Session: Theory
HK 9.16: Poster
Dienstag, 12. März 2002, 10:30–12:45, Foyer Chemie
Wide–angle Compton scattering and generalized parton distributions — •T. Oppermann1, A.V. Radyushkin2, A. Schäfer1, and C. Weiss1 — 1Institut für Theoretische Physik, Universität Regensburg, D–93053 Regensburg, Germany — 2Theory Group, Jefferson Lab, Newport News, VA 23606, USA, and Old Dominion University, Norfolk, VA 23529, USA
Real Compton scattering off the nucleon, γ N → γ N, at COM energies s ∼ few GeV2 and sufficiently large t (wide–angle Compton scattering, WACS) is measured in the Hall A experiment at JLAB. In QCD this process is dominated by Compton scattering off a single quark in the nucleon, accompanied by soft interactions with the spectator system (“soft mechanism”) [1]. The WACS amplitude can be expressed in terms of the so–called double distribution of quarks in the nucleon, which at small t can be related to the generalized parton distributions measured in hard exclusive electroproduction. We present estimates of the WACS cross section incorporating information about the structure and the modeling of the double distributions gained from studies of hard scattering processes, in particular the so–called D–term [2]. We also discuss the role of O(t/s) kinematical corrections to the WACS amplitude.
[1] A. V. Radyushkin, Phys. Rev. D58 (1998) 114008
[2] M. V. Polyakov and C. Weiss, Phys. Rev. D60 (1999) 114017