Twist-3 contribution to deeply virtual electroproduction of pions

Abstract

The twist-3 contribution, consisting of twist-2 transversity generalized parton distributions (GPDs) and a twist-3 meson wave function, to deeply virtual pion electroproduction is discussed. The twist-3 meson wave function includes both the $q\bar{q}$ and the $q\bar{q}g$ Fock components. Two methods to regularize the end-point singularities are introduced - quark transverse momenta and a gluon mass. Using existing GPD parameterizations the transverse and the transverse-transverse interference cross sections for ${\pi }^0$ production are calculated and compared to experimental data.

Comments: 40 pages, 10 figures; some improvements in the text and few typos corrected; corresponds to a published version