Does $ψ(4660)$ exist?
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arXiv
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| Format: | Preprint |
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2026
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| _version_ | 1866917461006221312 |
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| author | Wang, Xian-Chen Ye, Quanxing wang, Qian |
| author_facet | Wang, Xian-Chen Ye, Quanxing wang, Qian |
| contents | We investigate $S$-wave coupled-channel effects in $e^+e^-$ annihilation in the energy region $\sqrt{s}\in[4.0,5.5]\,\mathrm{GeV}$, including the open-charm final states $Λ_c^+\barΛ_c^-$, $Ξ_c^+\barΞ_c^-$, $Ξ_c^0\barΞ_c^0$, and $ψ(2S)π^+π^-$. Motivated by the recent high-precision BESIII measurements of the $e^+e^-\toΛ_c^+\barΛ_c^-$ cross section, which shows a nearly flat lineshape around $4.66~\mathrm{GeV}$ and a non-zero value right at threshold, in striking contrast to earlier Belle observation, we construct an effective coupled-channel framework by using short-ranged contact potentials in the heavy-quark limit.Two charmonium states, i.e. the $ψ(4360)$ and $ψ(4660)$, assigned as the $4S$ and $5S$ excitations, respectively, are explicitly included. The scattering amplitudes are obtained by solving the Lippmann-Schwinger equation.The Belle and BESIII $e^+e^-\toΛ_c^+\barΛ_c^-$ and $e^+e^-\toψ(2S)π^+π^-$ cross-sections reveal markedly different pole structures for the $ψ(4360)$. It emerges as a dynamically generated state for the Belle data, whereas it appears as a bare state in the BESIII fit. In contrast, the $ψ(4660)$ pole found on the unphysical Riemann sheet above the $Λ_c^+\barΛ_c^-$ threshold is associated with a bare pole on the real axis in both fits. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2605_03320 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Does $ψ(4660)$ exist? Wang, Xian-Chen Ye, Quanxing wang, Qian High Energy Physics - Phenomenology We investigate $S$-wave coupled-channel effects in $e^+e^-$ annihilation in the energy region $\sqrt{s}\in[4.0,5.5]\,\mathrm{GeV}$, including the open-charm final states $Λ_c^+\barΛ_c^-$, $Ξ_c^+\barΞ_c^-$, $Ξ_c^0\barΞ_c^0$, and $ψ(2S)π^+π^-$. Motivated by the recent high-precision BESIII measurements of the $e^+e^-\toΛ_c^+\barΛ_c^-$ cross section, which shows a nearly flat lineshape around $4.66~\mathrm{GeV}$ and a non-zero value right at threshold, in striking contrast to earlier Belle observation, we construct an effective coupled-channel framework by using short-ranged contact potentials in the heavy-quark limit.Two charmonium states, i.e. the $ψ(4360)$ and $ψ(4660)$, assigned as the $4S$ and $5S$ excitations, respectively, are explicitly included. The scattering amplitudes are obtained by solving the Lippmann-Schwinger equation.The Belle and BESIII $e^+e^-\toΛ_c^+\barΛ_c^-$ and $e^+e^-\toψ(2S)π^+π^-$ cross-sections reveal markedly different pole structures for the $ψ(4360)$. It emerges as a dynamically generated state for the Belle data, whereas it appears as a bare state in the BESIII fit. In contrast, the $ψ(4660)$ pole found on the unphysical Riemann sheet above the $Λ_c^+\barΛ_c^-$ threshold is associated with a bare pole on the real axis in both fits. |
| title | Does $ψ(4660)$ exist? |
| topic | High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2605.03320 |