{"paper":{"title":"Amplitude Analysis of the Isospin-Violating Decay $J/\\psi\\rightarrow\\gamma\\eta\\pi^{0}$","license":"http://creativecommons.org/licenses/by/4.0/","headline":"The first amplitude analysis of J/ψ → γ η π⁰ observes radiative transitions to isospin-triplet scalar mesons with over 5σ significance.","cross_cats":[],"primary_cat":"hep-ex","authors_text":"A. Amoroso, A. A. Zafar, A. Bortone, A. Brueggemann, A. Calcaterra, A. Dbeyssi, A. Denig, A. Gilman, A. Guskov, A. Khoukaz, A. Kupsc, A. Limphirat, A. Marshall, A. N. Zhu, A. Pathak, A. Q. Guo, A. Rivetti, A. Sarantsev, A. Zhemchugov, B. A. Shi, B. C. Ke, BESIII Collaboration: M. Ablikim, B. H. Xiang, Bin Wang, B. J. Liu, B. Kopf, B. L. Zhang, B. Moses, B. M. Zheng, Bo Wang, B. Wang, B. X. Liu, B. X. Yu, B. X. Zhang, B. Zheng, B. Zhong, C. C. Lin, C. D. Fu, C. F. Qiao, C. F. Redmer, C. Geng, Chao Chen, Chao Wang, C. H. Chen, C. Herold, C. H. Heinz, C. H. Li, Ch. Rosner, Chunkai Li, Ch. Y. Shi, C. J. Tang, C. J. Xu, C. K. Li, C. Li, C. Liang, C. Liu, C. L. Luo, C. Normand, Cong Li, Cong Wang, C. P. Shen, C. Q. Deng, C. Q. Feng, C. S. Akondi, C. Wang, C. Xie, C. X. Lin, C. X. Liu, C. X. Yu, C. X. Yue, C. Y. Guan, C. Z. He, C. Zhong, C. Z. Yuan, D. Bettoni, D. B. Xiong, D. Cabiati, D. Dedovich, D. H. Wei, D. H. Zhang, D. Jiang, D. J. Wei, D. M. Li, D. Wei, D. Xiao, D. X. Lin, D. Y. Wang, E. Bianco, E. Di Fiore, E. M. Gersabeck, E. van der Smagt, F. A. Harris, F. Bianchi, F. C. Ma, F. Cossio, F. De Mori, F. E. Maas, Feng Liu, F. Feldbauer, F. Hanisch, F. H. Heinsius, F. H. Liu, F. Li, F. Liu, F. M. Melendi, F. Nerling, F. Rosini, F. R. Zeng, F. Stieler, F. Weidner, F. Yan, F. Z. Qi, G. B. Sun, G. Chen, G. Cibinetto, Gengyuan Zhang, G. F. Cao, G. Felici, G. F. Fan, G. F. Xu, G. Li, G. L. Peng, G. Mezzadri, G. M. Liu, G. R. Che, G. R. Liao, G. Rong, G. S. Huang, G. Wilkinson, G. X. Sun, G. Y. Hou, G. Y. Tang, G. Yu, G. Y. Xiao, G. Y. Zhang, G. Zhao, Han Zhang, H. B. Jiang, H. B. Li, H. B. Liu, H. Cai, H. C. Zhang, Heng Ma, H. F. Shen, H. Gao, H. Guo, H. H. Zhang, H. J. Li, H. J. Lu, H. J. Wang, H. J. Yang, H. K. Sun, H. L. Dai, H. Liang, H. Liu, H. L. Li, H. L. Ma, H. L. Song, H. L. Xia, H. L. Yang, H. M. Hu, H. Miao, H. M. Liu, H. Neuwirth, H. N. Li, H. P. Li, H. P. Peng, H. Q. Zhang, H.-R. Bao, H. R. Qi, H. R. Wang, H. R. Wei, H. R. Wen, H. R. Zhang, H. S. Chen, H. Shi, H. Sun, H. Tabaharizato, Huihui Liu, Hui Li, H. Xiao, H. X. Mao, H. X. Yang, H. Y. Chen, H. Yuan, H. Y. Xu, H. Y. Zhang, H. Zhang, H. Zhou, I. Boyko, I. Denisenko, I. Garzia, I. Mackay, I. Uman, J. B. Gong, J. B. Jiao, J. B. Liu, J. Cheng, J. Cottee-Meldrum, J. D. Gong, J. Dong, J. Fang, J. F. Chang, J. F. Hu, J. F. Qiu, J. F. Shangguan, J. F. Sun, J. F. Wu, J. G. Lu, J. Gollub, J. Gutierrez, J. H. Feng, J. H. Qiao, J. H. Yang, J. H. Zou, Jianyu Zhang, Jie Yuan, Jin Fang, Jin Zhang, Jiyuan Zhang, J. Jackson, J. J. Fan, J. J. Liu, J. J. Qin, J. J. Song, J. J. Tang, J. J. Wang, J. J. Zhang, J. K. Jiao, J. L. Fu, J. Libby, J. L. Ma, J. L. Ping, J. L. Qin, J. L. Shi, J. L. Zhang, J. Muskalla, J. N. Guo, J. N. Li, J. P. Dai, J. P. Wang, J.-P. Zhao, J. P. Zheng, J. Q. Zhang, J. Q. Zhou, J. Rademacker, J. R. Luo, J. S. Li, J. S. Luo, J. S. Yu, J. S. Zhang, J. Tang, Junhao Yin, J. Wang, J. W. Li, J. W. Zhang, J. X. Teng, J. X. Zhang, J. Y. Han, J. Y. Shi, J. Y. Tian, J. Yuan, J. Y. Zhang, J. Y. Zhao, J. Zhang, J. Zhu, J. Zu, J. Z. Zhang, J. Z. Zhao, K. Begzsuren, K. D. Hao, Ke Liu, K. Goetzen, K. J. Xie, K. J. Zhu, K. K. He, K. L. He, K. Li, K. Liu, K. L. Li, K. Peters, K. Petridis, K. Schoenning, K. Sun, K. S. Zhu, Kun Liu, K. Wang, K. X. Huang, K. Y. Liu, K. Zhu, L. B. Guo, L. B. Liao, L. C. Liu, L. C. L. Jin, Lei Li, Lei Zhang, Lei Zhao, L. Fava, L. Feng, L. F. Tang, L. Ge, L. Gong, L. G. Shao, L. H. Wu, Lianjie Wu, Lin Zhu, L. J. Li, L. J. Wu, L. K. Jia, L. Kr\\\"oger, L. Kr\\\"ummel, L. Liu, L. L. Ma, L. L. Wang, L. M. Zhang, L. N. Cheng, L. P\\\"opping, L. Q. Huang, L. Q. Qin, L. R. Ma, L. Sun, Lu Liu, L. W. Wang, L. W. Yu, L. Xia, L. X. Zhu, L. Yan, L. Y. Dong, L. Y. Qin, L. Y. Tao, L. Yuan, L. Zhao, M. Barbagiovanni, M. B. Bertani, M. Berlowski, M. C. Du, M. Destefanis, M. D. Gu, M. Fritsch, M. Greco, M. G. Zhao, M. H. Cai, M. H. Gu, M. H. Li, M. H. Liao, M. H. Liu, M. H. Shi, M. H. Song, M. H. Ye, Mi Wang, M. J. Guo, M. Kuessner, M. K. Yuan, M. L. Chen, M. Lellmann, M. Maggiora, M. N. Achasov, M. Pelizaeus, M. Qi, M. Q. Jing, M. Q. Ruan, M. R. Li, M. Rolo, M. Schernau, M. Scodeggio, M. Shao, M. Stolte, M. Tat, M. T. Li, M. Wang, M. Wolke, M. X. Luo, M. Y. Dong, M. Ye, M. Zhuge, N. Berger, N. Cao, N. H\\\"usken, N. in der Wiesche, N. Kumar, N. Salone, N. Yu. Muchnoi, N. Y. Wang, N. Zhang, O. Bakina, O. B. Kolcu, P. Adlarson, P. B. Qin, P. C. Hong, P. Egorov, P. Huang, P. L. Li, P. L. Liu, P. R. Li, P. T. Ge, P. Zhang, Q. A. Malik, Q. An, Q. Ji, Q. J. Xu, Q. Lan, Q. Liu, Q. L. Niu, Q. M. Li, Q. M. Ma, Q. N. Xu, Q. Ouyang, Q. P. Hu, Q. P. Ji, Q. X. Feng, Q. X. Li, Q. Y. Zhang, Q. Zhang, Q. Z. Zhang, R. A. Briere, R. Aliberti, R. E. de Boer, R. E. Mitchell, R. G. Ping, R. J. Yang, R. Li, R. P. Guo, R. P. Zhao, R. Q. Ma, R. Sun, R. Y. Ma, R. Y. Zhang, S. A. Cetin, S. B. Liu, S. Garbolino, S. Gramigna, S. G. Wu, Shanshan Li, Shaoxu Du, Shulei Zhang, Shun Wang, S. H. Yuan, S. H. Zeng, S. H. Zhang, S. H. Zhu, S. J. Chen, S. Jin, S. J. Jiang, S. J. Zhao, S. Kabana, S. K. Choi, S. L. Hu, S. Li, S. L. Olsen, S. Maity, S. Malde, S. Marcello, S. M. Chen, S. M. Wu, S. Nisar, S. N. Zhang, S. Pacetti, S. Plura, S. P. Wen, S. Qian, S. S. Fang, S. Sosio, S. Spataro, S. S. Rong, S. S Su, S. S. Sun, S. Stansilaus, S. Wang, S. X. Du, S. X. Li, S. Y. Li, S. Y. Shi, S. Zhou, T. Chen, T. D. Xu, T. Hu, T. Hussain, T. J. Min, T. Johansson, T. J. Wang, T. J. Zhu, T. Lenz, T. Li, T. Lin, T. Liu, T. Luo, T. Ma, T. Sun, T. T. Chang, T. T. Han, T. T. Lei, T. Wang, T. Y. Li, T. Yu, T. Y. Xing, T. Z. Song, U. Wiedner, V. Batozskaya, V. Khachatryan, V. Prasad, W. B. Qian, W. B. Yan, W. Chen, W. C. Yan, W. D. Li, W. D. Niu, W. D. Zhu, W. G. Li, W. Gradl, W. H. Shen, W. H. Tian, W. H. Yan, W. Ji, W. J. Zheng, W. J. Zhu, W. K\\\"uhn, W. M. Liu, W. M. Song, W. N. Lan, W. P. Wang, W. P. Yan, W. Q. Zheng, W. Shan, W. T. Liu, W. Wang, W. X. Fang, W. X. Gong, W. Y. Sun, W. Z. Zhu, X. B. Ji, X. Cai, X. C. Ai, X. C. Dai, X. Chu, X. C. Lou, X. Dong, X. D. Yu, X. F. Wang, X. Guo, X. Han, X. H. Li, X. H. Mo, Xin Wang, X. J. Peng, X. K. Li, X. K. Liu, X. Kui, X. K. Zhou, X. L. Bao, X. L. Du, X. Li, X. Liu, X. L. Ji, X. L. Kang, X. L. Li, X. L. Liu, X. L. Lu, X. L. Luo, X. L. Wang, X. M. Jing, X. M. Zhang, X. N. Wang, X. Pan, X. P. Liu, X. P. Qin, X. P. Xu, X. Q. Hao, X. Q. Jia, X. Q. Yan, X. R. Chen, X. R. Lyu, X. R. Zheng, X. R. Zhou, X. Shi, X. S. Jiang, X. S. Kang, X. S. Qin, X. T. Chen, X. T. Hou, X. T. Huang, X. T. Ma, X. W. Wu, X. X. Ding, X. Y. Chai, X. Y. Chen, X. Y. Li, X. Y. Liu, X. Y. Ma, X. Y. Shan, X. Y. Shen, X. Y. Yang, X. Y. Zhang, X. Y. Zhou, X. Y. Zhuang, X. Zeng, X. Zhou, X. Z. Li, Yanning Wang, Yaqian Wang, Y. A. Tang, Y. Bai, Y. B. Chen, Y. B. Liu, Y. B. Zhao, Y. C. Sun, Y. C. Xu, Y. C. Yu, Y. C. Zhai, Y. C. Zhu, Y. Ding, Y. D. Wang, Y. F. Liang, Y. F. Lyu, Y. F. Wang, Y. Gao, Y. G. Li, Y. G. Xie, Y. H. An, Y. H. Fan, Y. H. Lu, Y. H. Lyu, Y. H. Meng, Y. H. Sun, Y. Hu, Y. H. Wang, Y. H. Xie, Y. H. Yang, Y. H. Zhan, Y. H. Zhang, Y. H. Zheng, Yi. Ding, Yi Liu, Ying Yue, Yi Wang, Y. Jiang, Y. Jin, Y. J. Mao, Y. J. Sun, Y. J. Wang, Y. J. Zeng, Y. K. Heng, Y. Li, Y. Liu, Y. Lu, Y. L. Wang, Y. L. Xiao, Y. L. Zhao, Y. M. Ma, Y. M. Yang, Y. Nefedov, Y. N. Gao, Y. Niu, Y. N. Wang, Yongchao Yu, Youhua Yang, Y. Pan, Y. P. Guo, Y. P. Huang, Y. P. Li, Y. P. Liao, Y. P. Lu, Y. P. Pei, Y. P. Zhang, Y. P. Zhao, Y. Q. Chen, Y. Q. Du, Y. Q. Fang, Y. Q. Yang, Y. R. Hou, Y. Schelhaas, Y. S. Huang, Y. T. Feng, Y. Tian, Y. T. Liang, Y. T. Zhang, Yuan Wang, Yujie Zeng, Yunong Gao, Yu Zhang, Y. Wang, Y. W. Fu, Y. X. Ding, Y. X. Hu, Y. Xie, Y. X. Song, Y. Xu, Y. X. Zhao, Y. X. Zhou, Y. Yang, Y. Y. Duan, Y. Y. Gao, Y. Y. Ji, Y. Y. Kuang, Y. Y. Peng, Y. Yuan, Y. Y. Yan, Y. Z. Che, Y. Zhang, Y. Z. Sun, Y. Z. Yang, Y. Z. Zhou, Z. A. Liu, Z. A. Zhu, Z. D. Liu, Z. D. Zhang, Z. F. Tian, Z. Gao, Z. Guo, Z. G. Zhao, Z. H. Duan, Zhilong Zhang, Zhi Wang, Z. H. Li, Z. H. Lu, Z. H. Qin, Z. H. Qu, Z. H. Tang, Z. H. Zhang, Zh. Zh. Zhang, Zirong Song, Ziyang Zhang, Ziyi Wang, Ziyu Zhang, Z. Jiao, Z. J. Li, Z. J. Shang, Z. J. Xiao, Z. J. Ye, Z. K. Chen, Z. K. Jia, Z. L. Hou, Z. L. Li, Z. L. Liu, Z. L. Wang, Z. L. Zhang, Z. M. Hu, Z. Ning, Z. P. Mao, Z. P. Xie, Z. P. Yao, Z. Q. Liu, Z. Q. Sun, Z. Q. Wang, Z. S. Xu, Z. T. Sun, Z. Wang, Z. W. Ge, Z. Wu, Z. X. Li, Z. X. Liu, Z. X. Meng, Z. X. Zhang, Z. Y. Deng, Z. Y. Li, Z. Y. Liu, Z. Y. Lv, Z. Y. Wang, Z. Y. Yang, Z. Y. You, Z. Y. Zhang, Z. Zhang","submitted_at":"2026-03-24T11:23:21Z","abstract_excerpt":"Using $(10\\,087 \\pm 44) \\times 10^6$ $J/\\psi$ events collected with the BESIII detector, we perform the first amplitude analysis of the process $J/\\psi\\to\\gamma\\eta\\pi^0$. The decay is dominated by the intermediate processes $J/\\psi\\to\\pi^0 b_1(1235)^0 \\to\\gamma\\eta\\pi^0$, $J/\\psi\\to\\pi^{0}\\rho(1450)^0 \\to\\gamma\\eta \\pi^0$ and $J/\\psi\\to\\eta h_1(1170) \\to\\gamma\\eta\\pi^0$. Contributions from $J/\\psi\\to\\gamma a_0(980)^0\\to\\gamma\\eta\\pi^0$, $J/\\psi\\to\\gamma a_2(1320)^0\\to\\gamma\\eta\\pi^0$ and $J/\\psi\\to\\gamma a_2(1700)^0\\to\\gamma\\eta\\pi^0$ are observed with a statistical significance exceeding $5\\"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Contributions from J/ψ → γ a₀(980)⁰, J/ψ → γ a₂(1320)⁰ and J/ψ → γ a₂(1700)⁰ are observed with statistical significance exceeding 5σ, constituting the first observation of radiative transitions of J/ψ to isospin-triplet scalar mesons.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The amplitude model includes only the listed resonances and assumes that interference and background shapes are correctly parameterized; an incomplete resonance list or unaccounted interference could alter the extracted significances and branching fractions.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"J/ψ → γ η π⁰ proceeds mainly via π⁰ b₁(1235)⁰, π⁰ ρ(1450)⁰ and η h₁(1170) intermediates, with first observations of J/ψ radiative decays to isospin-triplet scalars a₀(980), a₂(1320) and a₂(1700), and branching fraction (25.7 ± 0.3 ± 1.5) × 10^{-6}.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The first amplitude analysis of J/ψ → γ η π⁰ observes radiative transitions to isospin-triplet scalar mesons with over 5σ significance.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"4f6ed97eca8f29caf2b5b1c6840efffea1941349367bc7eab61ff9a6bb8c22da"},"source":{"id":"2603.23081","kind":"arxiv","version":2},"verdict":{"id":"61c5d753-0520-4627-8124-942ac864f2bb","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T00:35:45.329024Z","strongest_claim":"Contributions from J/ψ → γ a₀(980)⁰, J/ψ → γ a₂(1320)⁰ and J/ψ → γ a₂(1700)⁰ are observed with statistical significance exceeding 5σ, constituting the first observation of radiative transitions of J/ψ to isospin-triplet scalar mesons.","one_line_summary":"J/ψ → γ η π⁰ proceeds mainly via π⁰ b₁(1235)⁰, π⁰ ρ(1450)⁰ and η h₁(1170) intermediates, with first observations of J/ψ radiative decays to isospin-triplet scalars a₀(980), a₂(1320) and a₂(1700), and branching fraction (25.7 ± 0.3 ± 1.5) × 10^{-6}.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The amplitude model includes only the listed resonances and assumes that interference and background shapes are correctly parameterized; an incomplete resonance list or unaccounted interference could alter the extracted significances and branching fractions.","pith_extraction_headline":"The first amplitude analysis of J/ψ → γ η π⁰ observes radiative transitions to isospin-triplet scalar mesons with over 5σ significance."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2603.23081/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":58,"sample":[{"doi":"","year":1985,"title":"L. 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