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| Format: | Preprint |
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2025
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| Online Access: | https://arxiv.org/abs/2512.02655 |
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| _version_ | 1866917118918787072 |
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| author | Yan, Mao-Jun An, Chun-Sheng Deng, Cheng-Rong |
| author_facet | Yan, Mao-Jun An, Chun-Sheng Deng, Cheng-Rong |
| contents | We assess possible axial-vector states with $G$-parity $\left(G=\pm 1\right)$ dynamically generated by pseudoscalar-vector interactions in coupled channels, driven by the Weinberg-Tomozawa term at leading order in chiral perturbation theory. The $S$-wave amplitudes are unitarized via the Bethe-Salpeter equation, and poles of the unitarized amplitudes are searched for in the complex energy plane. In the isovector sector with $I^G(J^{PC})=1^{\pm}(1^{+\mp})$, we identify two poles around 1400 MeV in the second Riemann sheet below the $K^*\bar{K}$ mass threshold. The $G=+1$ and $G=-1$ poles can be one of the origins of the peaks in the $f_0(980)π$ and $ϕπ^0$ mass spectra reported by the COMPASS and BESIII collaborations, respectively, in the $πN \to πππN$ and $J/ψ\to ηϕπ$ processes, in addition to triangle singularity effects discussed in the literature. Additionally, the poles in the isoscalar sector may explain the nontrivial behavior of the $K^*\bar{K}$ spectra line shapes measured by several experiments in different reactions. Specifically, for the $0^+(1^{++})$ case, we find a sizeable $K^*\bar{K}$ component for the $f_1(1420)$. In the $0^-(1^{+-})$ scenario, the pole strongly coupled to $ρπ$ can be associated with the $h_1(1170)$ resonance. Lastly, in this same sector, we identify a higher pole that dominates the $K^*\bar{K}$ invariant mass in the $χ_{cJ} \to ϕK^*\bar{K}$ decay, where the \(h_1(1415)\) is observed in the BESIII data. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2512_02655 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Reevaluating the $a_1(1420)$ enhancement and its molecular partners in the low-lying axial-vector meson spectrum Yan, Mao-Jun An, Chun-Sheng Deng, Cheng-Rong High Energy Physics - Phenomenology We assess possible axial-vector states with $G$-parity $\left(G=\pm 1\right)$ dynamically generated by pseudoscalar-vector interactions in coupled channels, driven by the Weinberg-Tomozawa term at leading order in chiral perturbation theory. The $S$-wave amplitudes are unitarized via the Bethe-Salpeter equation, and poles of the unitarized amplitudes are searched for in the complex energy plane. In the isovector sector with $I^G(J^{PC})=1^{\pm}(1^{+\mp})$, we identify two poles around 1400 MeV in the second Riemann sheet below the $K^*\bar{K}$ mass threshold. The $G=+1$ and $G=-1$ poles can be one of the origins of the peaks in the $f_0(980)π$ and $ϕπ^0$ mass spectra reported by the COMPASS and BESIII collaborations, respectively, in the $πN \to πππN$ and $J/ψ\to ηϕπ$ processes, in addition to triangle singularity effects discussed in the literature. Additionally, the poles in the isoscalar sector may explain the nontrivial behavior of the $K^*\bar{K}$ spectra line shapes measured by several experiments in different reactions. Specifically, for the $0^+(1^{++})$ case, we find a sizeable $K^*\bar{K}$ component for the $f_1(1420)$. In the $0^-(1^{+-})$ scenario, the pole strongly coupled to $ρπ$ can be associated with the $h_1(1170)$ resonance. Lastly, in this same sector, we identify a higher pole that dominates the $K^*\bar{K}$ invariant mass in the $χ_{cJ} \to ϕK^*\bar{K}$ decay, where the \(h_1(1415)\) is observed in the BESIII data. |
| title | Reevaluating the $a_1(1420)$ enhancement and its molecular partners in the low-lying axial-vector meson spectrum |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2512.02655 |