Exclusive photoproduction of $D$-meson pairs with large invariant mass

TL;DR

This paper investigates the exclusive photoproduction of D-meson pairs with large invariant mass using collinear factorization, aiming to probe generalized parton distributions (GPDs) at the future Electron Ion Collider.

Contribution

It provides the first evaluation of D-meson pair photoproduction cross-sections in terms of GPDs, highlighting its potential to isolate contributions from individual light-flavor GPDs.

Findings

Cross-sections are sizable for experimental detection.

Process is sensitive to GPDs in the ERBL region.

Gluons and light quarks contribute comparably to the amplitude.

Abstract

In this paper we analyze the exclusive photoproduction of the $D$-meson pairs with large invariant mass. We perform evaluations in the collinear factorization framework and in the leading order of the strong coupling $\alpha_{s}$, expressing the cross-section in terms of generalized parton distributions (GPDs) of different parton flavors in the proton. We focus on the photoproduction of the pseudoscalar-vector pairs, like e.g. $D^{\pm}D^{*\mp}$, $D^{0}\overline{D}^{*0}$, $D_{s}^{+}D_{s}^{*-}$, which gets the dominant contribution from the chiral even GPDs of the target, and estimate the cross-section in the kinematics of the future Electron Ion Collider (EIC). In all channels the amplitude of the process obtains comparable contributions from gluons and only one of the light quark flavors. This finding signals that the process potentially could be used to single out the contributions of the individual chiral even GPDs of light flavors. We found that the process is mostly sensitive to the behavior of GPDs in the so-called Efremov-Radyushkin-Brodsky-Lepage (ERBL) region. Numerically, the cross-section of the process is sufficiently large for experimental studies and thus can be used as a complementary probe for studies of the partons GPDs.