Revealing di-pion correlations for the observed substructure near the π⁺π^- mass threshold in ψ(3686)→ J/ψπ⁺π^-

2025/11/13 by Wang, Zhong-Yu, Liu, Zhe, Liu, Xiang
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)

paper · doi:10.48550/arxiv.2511.10345

Abstract

Based on the world's largest ψ(3686) data sample, the BESIII Collaboration recently reported a substructure near the π⁺π^- mass threshold in the decay ψ(3686) → J/ψπ⁺π^-, challenging the established understanding of the di-pion invariant mass spectrum. We propose that this substructure arises directly from di-pion correlations. Using a chiral unitary approach, we successfully reproduce the observed anomaly, thereby providing strong evidence of di-pion correlation in heavy quarkonium decays. This approach also allows us to predict the corresponding di-pion correlation function.

Related

• Decoding the structure near the π⁺π^- mass threshold in ψ(3686) → J/ψπ⁺π^- decays
• Observation of a resonance-like structure near the π⁺π^- mass threshold in ψ(3686) → π⁺π^-J/ψ
• Probing the di-J/Ψ interaction and the nature of X(6200) with femtoscopic correlation functions
• Dropping Sigma-Meson Mass and In-Medium Pion-Pion Correlations
• Di-nucleons do not form bound states at heavy pion mass