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arXiv · 2602.20526

Update analysis of $\psi(3686)\to p\bar{p}$

Zhi Gao·Ronggang Ping·Minggang Zhao
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Abstract

We present an updated analysis of the angular distribution for $\psi(3686) \to p\bar{p}$ decay, taking into account transverse beam polarization, to investigate potential sources of forward-backward asymmetry and azimuthal modulation beyond the simple $1+\alpha\cos^2\theta$ form. We focus on the interference between the $\psi(3686)$ resonance and the two-photon exchange continuum process, as well as the background from initial-state-final-state radiation interference. A maximum-likelihood fit to the $\cos\theta$ distribution of $\psi(3686)\to p\bar{p}$ yields $\alpha = 1.00 \pm 0.03$, consistent with previous results. Our model predicts a significant $\sin(2\phi)$ modulation in the azimuthal angle, indicating the influence of transverse beam polarization. These findings motivate future two-dimensional angular analyses to fully disentangle the polarization and interference dynamics in charmonium decays to baryon pairs.

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Zhi Gao, Ronggang Ping, Minggang Zhao. 2026-02-24. Update analysis of $\psi(3686)\to p\bar{p}$. https://arxiv.org/abs/2602.20526

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