重夸克自旋进动作为磁场计时器
Heavy-quark spin precession as a magnetic field chronometer
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中文总结 AI 辅助
提出利用重夸克自旋进动作为探针，通过测量粲和底夸克极化劈裂来量化相对论性重离子碰撞中磁场的寿命和分布，为研究夸克-胶子等离子体提供新手段。
中文摘要 AI 辅助
在相对论性重离子碰撞中产生的强磁场寿命，仍然是夸克-胶子等离子体研究中一个主要未解问题。我们提出将重夸克自旋进动作为探针，用以量化此类碰撞中的磁场及其分布。我们研究了在磁场存在下，极化的粲夸克和底夸克在膨胀的夸克-胶子等离子体中传播时的拉莫尔进动演化。我们表明，现实强度的磁场及其寿命能够在强子化之前产生可测量的累积进动相位，通过横向和纵向极化分量的混合，导致$\Lambda_c^+$与$\bar{\Lambda}_c^-$之间以及$\Lambda_b^0$与$\bar{\Lambda}_b^0$之间出现特征性的电荷依赖极化劈裂。预测的信号表现出独特的横动量和夸克质量依赖性，在粲和底扇区对磁场寿命提供互补的灵敏度。我们的结果表明，重味极化，尤其是粲扇区，可作为相对论性重离子碰撞中磁场时空演化的定量探针。
英文摘要
The lifetime of the strong magnetic field generated in relativistic heavy-ion collisions remains one of the major open questions in the study of the quark--gluon plasma. We propose heavy-quark spin precession as a probe to quantify the magnetic field and its profile in such collisions. We investigate the Larmor evolution of polarized charm and bottom quarks propagating through an expanding quark--gluon plasma in the presence of the magnetic field. We show that realistic magnetic-field strengths and lifetimes generate measurable accumulated precession phases prior to hadronization, leading to characteristic charge-dependent polarization splittings between $Λ_c^+$ and $\barΛ_c^-$, as well as between $Λ_b^0$ and $\barΛ_b^0$, through the mixing of transverse and longitudinal polarization components. The predicted signals exhibit distinctive transverse-momentum and quark-mass dependence, providing complementary sensitivity to the magnetic-field lifetime in the charm and bottom sectors. Our results suggest heavy-flavor polarization, especially in the charm sector, as a quantitative probe for the space--time evolution of magnetic fields in relativistic heavy-ion collisions.
发表机构
- Instituto de Ciencias Nucleares, UNAM（墨西哥国立自治大学核科学研究所）
- School of Physical Sciences, National Institute of Science Education and Research（印度国家科学教育与研究学院物理科学学院）
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