Deeply virtual Compton scattering on a virtual pion target

TL;DR

This paper investigates deeply virtual Compton scattering on a virtual pion emitted by a proton, evaluating cross sections and asymmetries using models for pion generalized parton distributions, and discusses experimental feasibility and a new GPD parameterization.

Contribution

It introduces a new parameterization of pion generalized parton distributions that aligns with form factor data and lattice results, and assesses experimental conditions for scattering measurements.

Findings

Cross section and asymmetry calculations for DVCS on a virtual pion.

Experimental requirements are high but feasible after Jefferson Laboratory's energy upgrade.

A new pion GPD parameterization consistent with existing data.

Abstract

We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge asymmetries in the leading-twist approximation. Studying Compton scattering on the pion in suitable kinematics puts high demands on both beam energy and luminosity, and we find that the corresponding requirements will first be met after the energy upgrade at Jefferson Laboratory. As a by-product of our study, we construct a parameterization of pion generalized parton distributions that has a non-trivial interplay between the x and t dependence and is in good agreement with form factor data and lattice calculations.