Eur. Phys. J. A (2015) 51: 103
https://doi.org/10.1140/epja/i2015-15103-3

Regular Article - Theoretical Physics

Timelike Compton scattering off the proton and generalized parton distributions

¹ Institut de Physique Nucléaire d’Orsay, CNRS-IN2P3, Université Paris-Sud, F-91406, Orsay, France
² Institut für Kernphysik and PRISMA Cluster of Excellence, Johannes Gutenberg Universität, D-55099, Mainz, Germany

^* e-mail: guidal@ipno.in2p3.fr

Received: 7 January 2015
Revised: 21 July 2015
Accepted: 27 July 2015
Published online: 21 August 2015

Abstract

We study the exclusive photoproduction of a lepton pair off the proton with the aim of studying the proton quark structure via the Generalized Parton Distributions (GPD) formalism. After deriving the amplitudes of the processes contributing to the γP → P′ e ⁺ e ⁻, the timelike Compton scattering and the Bethe-Heitler process, we calculate all unpolarized, single- and double- spin beam-target observables in the valence region in terms of GPDs.