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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/2605.03320 |
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Table of 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.