Pseudoscalar Meson Electroproduction and Tranversity

TL;DR

This paper explores how pseudoscalar meson electroproduction can be used to access chiral odd GPDs related to transversity, revealing their dependence on nucleon tensor charge and other transversity parameters.

Contribution

It demonstrates that pseudoscalar production isolates chiral odd GPDs and analyzes the sensitivity of observables to transversity and tensor charge, advancing understanding of nucleon structure.

Findings

Pseudoscalar production isolates chiral odd GPDs.

Cross sections and asymmetries depend on transversity parameters.

Analyticity limits the partonic interpretation in the ERBL region.

Abstract

Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and gluon-parton functions. The chiral even subset of 4 quark-nucleon GPDs are related to nucleon form factors and to parton distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related to transversity, the tensor charge, and other quantities related to transversity. Different meson or photon production processes access different combinations of GPDs. This is analyzed in terms of $t$-channel exchange quantum numbers, $J^{PC}$ and it is shown that pseudoscalar production can isolate chiral odd GPDs. There is a sensitive dependence in various cross sections and asymmetries on the tensor charge of the nucleon and other transversity parameters. In a second section, analyticity and completeness are shown to limit the partonic interpretation of the GPDs in the ERBL region.