Decoding the structure near the $π^+π^-$ mass threshold in $ψ(3686) \rightarrow J/ψπ^+π^-$ decays
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arXiv
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| Hauptverfasser: | , , , , |
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| Format: | Preprint |
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2025
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| _version_ | 1866917334211362816 |
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| author | Chen, Yun-Hua Dong, Xiang-Kun Guo, Feng-Kun Hanhart, Christoph Kubis, Bastian |
| author_facet | Chen, Yun-Hua Dong, Xiang-Kun Guo, Feng-Kun Hanhart, Christoph Kubis, Bastian |
| contents | In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition $ψ(3686) \rightarrow J/ψπ^+π^-$. The strong pion-pion final-state interactions are taken into account model-independently by using dispersion theory. We find that we can reproduce the substructure near the $π^+π^-$ threshold observed experimentally without introducing an extra resonance state. While a helicity-flip amplitude plays an important role for the formation of the dip in the invariant-mass distribution, the virtual exchange of the charmoniumlike exotic $Z_c(3900)$ state improves the fit quality only slightly. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_01679 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Decoding the structure near the $π^+π^-$ mass threshold in $ψ(3686) \rightarrow J/ψπ^+π^-$ decays Chen, Yun-Hua Dong, Xiang-Kun Guo, Feng-Kun Hanhart, Christoph Kubis, Bastian High Energy Physics - Phenomenology High Energy Physics - Experiment Nuclear Theory In light of recent high-precision data taken by the BESIII Collaboration, we reconsider the dipion transition $ψ(3686) \rightarrow J/ψπ^+π^-$. The strong pion-pion final-state interactions are taken into account model-independently by using dispersion theory. We find that we can reproduce the substructure near the $π^+π^-$ threshold observed experimentally without introducing an extra resonance state. While a helicity-flip amplitude plays an important role for the formation of the dip in the invariant-mass distribution, the virtual exchange of the charmoniumlike exotic $Z_c(3900)$ state improves the fit quality only slightly. |
| title | Decoding the structure near the $π^+π^-$ mass threshold in $ψ(3686) \rightarrow J/ψπ^+π^-$ decays |
| topic | High Energy Physics - Phenomenology High Energy Physics - Experiment Nuclear Theory |
| url | https://arxiv.org/abs/2512.01679 |