Timelike deeply virtual Compton scattering with a linearly polarized real (or quasi-real) photon beam

TL;DR

This paper calculates timelike virtual Compton scattering amplitudes in the generalized Bjorken regime, introducing a new polarization asymmetry with a linearly polarized photon beam to probe polarized parton distributions at medium energies.

Contribution

It presents the first calculation of a new polarization asymmetry in timelike virtual Compton scattering, enabling access to polarized generalized parton distributions.

Findings

Identification of a new polarization asymmetry observable.

Potential to access polarized GPDs $ ilde H$ and $ ilde E$.

Relevance for upcoming JLab12 experiments.

Abstract

We calculate timelike virtual Compton scattering amplitudes in the generalized Bjorken scaling regime and focus on a new polarization asymmetry in the scattering process with a linearly polarized photon beam in the medium energy range, which will be studied intensely at JLab12 experiments. We demonstrate that new observables help us to access the polarized quark and gluon generalized parton distributions $\tilde H(x, \xi, t)$ and $ \tilde E(x, \xi, t)$.