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| Main Authors: | , , |
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| Format: | Preprint |
| Published: |
2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2603.29208 |
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| _version_ | 1866912990580703232 |
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| author | Jia, Zhao-Sai Li, Gang Zhang, Zhen-Hua |
| author_facet | Jia, Zhao-Sai Li, Gang Zhang, Zhen-Hua |
| contents | The cusp structure at the $π^+π^-$ threshold in the $π^0π^0$ invariant mass spectrum serves as a sensitive probe for extracting the $S$-wave $ππ$ scattering lengths in processes where an $S$-wave $π^0π^0$ pair is produced in the final states. Within the framework of nonrelativistic effective field theory with coupled channels $π^0π^0$ and $π^+π^-$, we revisit the near-threshold structures in the $π^0π^0$ spectrum of $ψ^\prime \to J/ψππ$. Our analysis incorporates the $ππ$ final-state rescattering, including both strong and Coulomb interactions. It turns out that the cusp near the $π^+π^-$ threshold becomes more prominent when Coulomb interactions are included. The electromagnetic correctionsare found to alter the magnitude of the threshold cusp by about 2%-3%, underscoring the necessity of including these effects in precision determinations of the $ππ$ scattering lengths. The coupled-channel amplitude constructed in this work provides a ready-to-use theoretical framework for experimental analyses of fine structures near $ππ$ thresholds. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2603_29208 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Role of electromagnetic corrections in the $ππ$ distributions of $ψ^\prime \to J/ψππ$ Jia, Zhao-Sai Li, Gang Zhang, Zhen-Hua High Energy Physics - Phenomenology The cusp structure at the $π^+π^-$ threshold in the $π^0π^0$ invariant mass spectrum serves as a sensitive probe for extracting the $S$-wave $ππ$ scattering lengths in processes where an $S$-wave $π^0π^0$ pair is produced in the final states. Within the framework of nonrelativistic effective field theory with coupled channels $π^0π^0$ and $π^+π^-$, we revisit the near-threshold structures in the $π^0π^0$ spectrum of $ψ^\prime \to J/ψππ$. Our analysis incorporates the $ππ$ final-state rescattering, including both strong and Coulomb interactions. It turns out that the cusp near the $π^+π^-$ threshold becomes more prominent when Coulomb interactions are included. The electromagnetic correctionsare found to alter the magnitude of the threshold cusp by about 2%-3%, underscoring the necessity of including these effects in precision determinations of the $ππ$ scattering lengths. The coupled-channel amplitude constructed in this work provides a ready-to-use theoretical framework for experimental analyses of fine structures near $ππ$ thresholds. |
| title | Role of electromagnetic corrections in the $ππ$ distributions of $ψ^\prime \to J/ψππ$ |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2603.29208 |