Hard exclusive photoproduction of photon-meson pairs: pseudoscalar channels $π$, $η$ and $η'$
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| Autores principales: | , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2025
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| author | Crnković, Nikola Duplančić, Goran Nabeebaccus, Saad Passek-K., Kornelija Pire, Bernard Szymanowski, Lech Wallon, Samuel |
| author_facet | Crnković, Nikola Duplančić, Goran Nabeebaccus, Saad Passek-K., Kornelija Pire, Bernard Szymanowski, Lech Wallon, Samuel |
| contents | We investigate the hard exclusive photoproduction of photon-meson pairs at leading-twist and leading-order in perturbative QCD, and focus on pseudoscalar mesons $\text{M} \in \{π^\pm, π^0, η, η'\}$. Compact analytical expressions are obtained for the amplitudes involving quark generalized parton distributions, with the two-gluon components of the $η$ and $η'$ distribution amplitudes included. The numerical analysis is performed in the moderate-$ξ$ region, where valence-quark GPDs are expected to be important. In this region, we find a strong impact of the pion-pole term in $γπ^\pm$ production, and a non-negligible effect for neutral mesons. We also observe a marked dependence of $γη'$ photoproduction on two-gluon contributions. This process offers enhanced sensitivity to the shape of the GPDs already at leading-order, while the tested dependence on the meson distribution amplitude and the renormalization scale introduces further theoretical uncertainties, the latter emphasizing the need for next-to-leading-order corrections. Our results provide a concise analytical framework and a numerical baseline for future studies. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2511_19720 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Hard exclusive photoproduction of photon-meson pairs: pseudoscalar channels $π$, $η$ and $η'$ Crnković, Nikola Duplančić, Goran Nabeebaccus, Saad Passek-K., Kornelija Pire, Bernard Szymanowski, Lech Wallon, Samuel High Energy Physics - Phenomenology High Energy Physics - Experiment We investigate the hard exclusive photoproduction of photon-meson pairs at leading-twist and leading-order in perturbative QCD, and focus on pseudoscalar mesons $\text{M} \in \{π^\pm, π^0, η, η'\}$. Compact analytical expressions are obtained for the amplitudes involving quark generalized parton distributions, with the two-gluon components of the $η$ and $η'$ distribution amplitudes included. The numerical analysis is performed in the moderate-$ξ$ region, where valence-quark GPDs are expected to be important. In this region, we find a strong impact of the pion-pole term in $γπ^\pm$ production, and a non-negligible effect for neutral mesons. We also observe a marked dependence of $γη'$ photoproduction on two-gluon contributions. This process offers enhanced sensitivity to the shape of the GPDs already at leading-order, while the tested dependence on the meson distribution amplitude and the renormalization scale introduces further theoretical uncertainties, the latter emphasizing the need for next-to-leading-order corrections. Our results provide a concise analytical framework and a numerical baseline for future studies. |
| title | Hard exclusive photoproduction of photon-meson pairs: pseudoscalar channels $π$, $η$ and $η'$ |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment |
| url | https://arxiv.org/abs/2511.19720 |