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Auteurs principaux: Jia, Yu, Zhou, Jian, Zhou, Ya-jin
Format: Preprint
Publié: 2024
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Accès en ligne:https://arxiv.org/abs/2406.09381
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author Jia, Yu
Zhou, Jian
Zhou, Ya-jin
author_facet Jia, Yu
Zhou, Jian
Zhou, Ya-jin
contents In this work we advocate a set of novel azimuthal-angle-related observables associated with exclusive hadron production from two-photon fusion at $e^+ e^-$ colliders, taking the $γγ\to ππ$ as a benchmark process. As a direct consequence of the linearly polarized quasi-real photons emitted off the electron and positron beams, the $\cos 2ϕ$ azimuthal asymmetry in dipion production is predicted within the transverse-momentum-dependent (TMD) factorization framework. In numerical analysis, we take the helicity amplitudes of $γγ\to ππ$ determined from the partial wave solutions in dispersion relation as input, and find that the predicted $\cos2ϕ$ azimuthal modulation may reach 40\% for the typical kinematical setup of {\tt Belle 2} and {\tt BESIII} experiments. Future accurate measurement of this azimuthal asymmetry may facilitate the direct extraction of the relative phase between two helicity amplitudes with photon helicity configurations $++$ and $+-$. This knowledge provides a valuable input for the dispersive determination of the hadronic light-by-light (Hlbl) contributions.
format Preprint
id arxiv_https___arxiv_org_abs_2406_09381
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Novel azimuthal observables from two-photon collision at $e^+e^-$ colliders
Jia, Yu
Zhou, Jian
Zhou, Ya-jin
High Energy Physics - Phenomenology
High Energy Physics - Experiment
In this work we advocate a set of novel azimuthal-angle-related observables associated with exclusive hadron production from two-photon fusion at $e^+ e^-$ colliders, taking the $γγ\to ππ$ as a benchmark process. As a direct consequence of the linearly polarized quasi-real photons emitted off the electron and positron beams, the $\cos 2ϕ$ azimuthal asymmetry in dipion production is predicted within the transverse-momentum-dependent (TMD) factorization framework. In numerical analysis, we take the helicity amplitudes of $γγ\to ππ$ determined from the partial wave solutions in dispersion relation as input, and find that the predicted $\cos2ϕ$ azimuthal modulation may reach 40\% for the typical kinematical setup of {\tt Belle 2} and {\tt BESIII} experiments. Future accurate measurement of this azimuthal asymmetry may facilitate the direct extraction of the relative phase between two helicity amplitudes with photon helicity configurations $++$ and $+-$. This knowledge provides a valuable input for the dispersive determination of the hadronic light-by-light (Hlbl) contributions.
title Novel azimuthal observables from two-photon collision at $e^+e^-$ colliders
topic High Energy Physics - Phenomenology
High Energy Physics - Experiment
url https://arxiv.org/abs/2406.09381