Transversity in hard exclusive electroproduction of pseudoscalar mesons

TL;DR

This paper investigates the electroproduction of pseudoscalar mesons at small skewness using the handbag approach, highlighting the significant role of transversity GPDs and their impact on transverse cross sections.

Contribution

It introduces a method to incorporate transversity GPDs with twist-3 meson wave functions into the handbag approach for pseudoscalar meson electroproduction.

Findings

Large transverse cross sections for most channels due to transversity GPDs.

Constrains on GPDs from lattice QCD moments.

Significant role of H-tilde_T and E-bar_T in cross section calculations.

Abstract

Estimates for electroproduction of pseudoscalar mesons at small values of skewness are presented. Cross sections and asymmetries for these processes are calculated within the handbag approach which is based on factorization in hard parton subprocesses and soft generalized parton distributions (GPDs). The latter are constructed from double distributions. Transversity GPDs are taken into account; they are accompanied by twist-3 meson wave functions. For most pseudoscalar-meson channels a combination of H-tilde_T$ and E-bar_T$ plays a particularly prominent role. This combination of GPDs which we constrain by moments obtained from lattice QCD, leads with the exception of the pi+ and eta' channels, to large transverse cross sections.