Transversity Generalized Parton Distributions from gamma N -> pi rhot N' with a Large pi rhot Invariant Mass

TL;DR

This paper explores how to experimentally access the transversity generalized parton distributions of the nucleon via exclusive photoproduction of a pi rhoT meson pair with large invariant mass, using perturbative calculations and modeling.

Contribution

It introduces a method to probe transversity GPDs through gamma N -> pi rhoT N' process with a focus on the large invariant mass regime and provides a simple model for H_T(x, xi, t).

Findings

Perturbative scattering amplitude calculated at leading order.

A simple double distribution model for H_T(x, xi, t) proposed.

Counting rate estimates are underway.

Abstract

The chiral-odd transversity generalized parton distributions of the nucleon can be accessed experimentally through the exclusive photoproduction process gamma N -> pi rhoT N', with or without beam and target polarization, provided the vector meson is produced in a transversely polarized state. The kinematical domain of factorization is defined through a large invariant mass of the meson pair and a small transverse momentum of the final nucleon. We calculate perturbatively the scattering amplitude at leading order in alpha_s and build a simple model for the dominant transversity GPD H_T(x, xi, t) based on the concept of double distribution. Counting rate estimates are in progress.