发表机构
Indian Institute of Technology Indore; National Institute of Science Education and Research（印度理工学院印多尔分校; 国家科学教育研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过福克-普朗克方程和自旋-涡度耦合，解析推导了强磁场下粲夸克旋转布朗运动导致的$\mathrm{J/\psi}$自旋密度矩阵元$\rho_{00}$，提出旋转扩散是重离子碰撞中$\mathrm{J/\psi}$自旋排列的可能机制。
AI 中文摘要
在超相对论重离子碰撞（HICs）中，重夸克极化可作为揭示退禁闭QCD特性的探针。本研究通过考虑强磁场中粲夸克的旋转布朗运动，探讨了HICs中$\mathrm{J/\psi}$的自旋排列。我们基于福克-普朗克方程，在考虑自旋-涡度耦合的情况下，推导了$c$-$\bar{c}$对极化的解析表达式。这些极化的$c$-$\bar{c}$对通过融合和碎裂机制在强子化表面形成$\mathrm{J}/\psi$。相应地，我们得到了$\mathrm{J}/\psi$自旋密度矩阵的$m=0$对角元$\rho_{00}$，它量化了沿所选量子化轴的自旋排列。我们的研究提供了重夸克自旋输运的微观描述，并表明旋转扩散可能是观测到的$\mathrm{J}/\psi$自旋排列背后的潜在机制。
英文摘要
The heavy-quark polarization in ultra-relativistic heavy-ion collisions (HICs) serves as a probe for unfolding the characteristics of deconfined QCD. The present study explores the spin alignment of $\mathrm{J/ψ}$ in the HICs by employing the rotational Brownian motion of charm quarks in the presence of a strong magnetic field. We derive an analytical expression for the polarization of the $c$-$\bar{c}$ pair based on the Fokker-Planck equation under the consideration of spin-vorticity coupling. These polarized $c$-$\bar{c}$ pairs lead to the formation of the $\mathrm{J}/ψ$ at the hadronization surface via the coalescence and fragmentation mechanisms. Correspondingly, we obtain the $m=0$ diagonal element $ρ_{00}$ of the $\mathrm{J}/ψ$ spin-density matrix, which quantifies its spin alignment along the chosen quantization axis. Our study provides a microscopic description of heavy-quark spin transport and suggests rotational diffusion as a possible mechanism underlying the observed $\mathrm{J}/ψ$ spin alignment.
Comments9 pages, 2 figures
