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arXiv:2512.22837 · Physical review. D/Physical review. D.

Bell nonlocality and entanglement in $χ_{cJ}$ decays into baryon pair

PengCheng Hong, RongGang Ping, WeiMin Song

hep-phhep-exquant-phSubmitted Dec 28, 2025• Announced Dec 30, 2025• 1 citation
v1 · Dec 28, 2025v2 · Mar 15, 2026
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Abstract

We present a systematic analysis of Bell nonlocality and entanglement in $χ_{cJ}$ decays into baryon pair ($B\bar{B}$) ($J=0,1,2$). From the baryon-antibaryon spin density matrix, we construct measurable Bell observables and concurrence, revealing a striking hierarchy of quantum correlations: $χ_{c0}$ decays exhibit maximal violation and entanglement; $χ_{c1}$ decays violate Bell inequalities for $θ_1 \in (0, π)$ with angle-modulated strength; we find that $B\bar B$ in $χ_{c2}$ decays is in separable state, and no indication is found for the Bell inequality violation. We provide complete analytical results for $J=0,1$ and quantitative, uncertainty-aware estimations for $J=2$ using experimental inputs. The results indicates that the $χ_{cJ}$ system as a novel platform for testing quantum entanglement in high-energy collisions.

DOI
10.1103/8bx4-gfc4
Comments
9 pages, 5 figures

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