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arXiv · 2608.22927

Disentangling isospin violation in charmonia decaying into $\Xi \overline \Xi$ pairs

Huan-Ran Wen·Chun-Qiu Zhao·Xu Cao·Jian-Ping Dai
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Abstract

Based on a model-independent isospin decomposition, we perform a data-driven analysis of $J/\psi$ and $\psi(2S)$ decays into $\Xi \bar{\Xi}$ pairs by leveraging the full set of observables from high-statistics BESIII data. We find that the isospin-violating amplitudes are predominantly driven by the electric couplings, with magnitudes reaching approximately 10%, contrasting with the smaller magnetic contributions of about 3%. A partial-wave analysis further reveals that $S$-wave isospin violation is comparable to the $D$-wave contribution.

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Huan-Ran Wen, Chun-Qiu Zhao, Xu Cao, Jian-Ping Dai. 2026-08-24. Disentangling isospin violation in charmonia decaying into $\Xi \overline \Xi$ pairs. https://arxiv.org/abs/2608.22927

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