Transversity GPD in photo- and electroproduction of two vector mesons

Abstract

The chiral-odd generalized parton distribution (GPD), or transversity GPD, of the nucleon can be accessed experimentally through the photo- or electroproduction of two vector mesons on a polarized nucleon target, \gamma^(*) N --> \rho_1 \rho_2 N', where \rho_1 is produced at large transverse momentum, \rho_2 is transversely polarized, and the mesons are separated by a large rapidity gap. We predict the cross section for this process for both transverse and longitudinal \rho_{2} production. To this end we propose a model for the transversity GPD H_T(x,\xi,t), and give an estimate of the relative sizes of the transverse and longitudinal \rho_{2} cross sections. We show that a dedicated experiment at high energy should be able to measure the transversity content of the proton.

Comments: 15 pages, 9 figures. Extended discussion of experimental prospects in the conclusions. Version to appear in EPJ C