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arXiv · 2212.01034

Accessing GPDs through the exclusive photoproduction of a photon-meson pair with a large invariant mass

Goran Duplančić·Saad Nabeebaccus·Kornelija Passek-Kumerički·Bernard Pire·Lech Szymanowski·Samuel Wallon
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Abstract

We study the exclusive photoproduction of a photon-meson pair with a large invariant mass, working in the QCD factorisation framework. Explicitly, we consider a $ \rho $-meson or a charged $ \pi $ in the final state. This process gives access to chiral-even GPDs as well as chiral-odd GPDs. We focus here on the chiral-even sector. The computation is performed at leading order and leading twist. We discuss the prospects of measuring them in various experiments such as JLab 12-GeV, COMPASS, future EIC and LHC (in ultraperipheral collisions). In particular, the high centre of mass energies available at collider experiments can be used to probe GPDs at small skewness $ \xi $. We also compute the polarisation asymmetries with respect to the incoming photon. The results for an alternative distribution amplitude (`holographic' form) are also compared with the predictions obtained with an asymptotic distribution amplitude.

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Goran Duplančić, Saad Nabeebaccus, Kornelija Passek-Kumerički, Bernard Pire, Lech Szymanowski, Samuel Wallon. 2022-12-02. Accessing GPDs through the exclusive photoproduction of a photon-meson pair with a large invariant mass. https://arxiv.org/abs/2212.01034

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