实验室系T矩阵与夸克胶子等离子体中的重夸克拖曳
Laboratory-frame $T$-matrix and heavy quark drag in the quark-gluon plasma
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中文总结 AI 辅助
本研究开发了直接在实验室系求解介质中两体T矩阵的框架，将其应用于QGP中的重轻夸克散射，使低动量下重夸克拖曳系数得到25%-40%的修正，降低了QGP输运性质提取的理论不确定性。
中文摘要 AI 辅助
非微扰散射T矩阵是强耦合介质中输运现象评估的核心输入。现有的介质中T矩阵计算通常在两粒子质心系中进行，散射方程可简化为低维问题。然而，介质明确破坏洛伦兹不变性并定义了一个优选参考系，要求物理可观测量由介质静止（实验室）系中计算的散射振幅构建。本研究利用散射对动量轴的旋转对称性，开发了一种可直接在实验室系中求解介质中两体T矩阵的实用框架，同时保留了对总对动量和散射几何的完整依赖。研究表明，所得振幅与传统质心系结果存在显著差异；将其应用于夸克胶子等离子体（QGP）中的重轻夸克散射时，低动量下重夸克拖曳系数会得到25%-40%的修正，从而消除了利用重夸克探针提取QGP输运性质时的一个重要理论不确定源。
英文摘要
Non-perturbative scattering $T$-matrix is a core input for the evaluation of transport phenomena in a strongly-coupled medium. Existing in-medium $T$-matrix calculations are typically formulated in the two-particle center-of-mass frame, where the scattering equation can be reduced to a lower-dimensional problem. However, a medium explicitly breaks Lorentz invariance and defines a preferred reference frame, entailing that physical observables be constructed from scattering amplitudes evaluated in the medium rest (laboratory) frame. In this work, by exploiting the rotational symmetry about the scattering-pair-momentum axis, we develop a practical framework for solving the in-medium two-body $T$-matrix directly in the laboratory frame while retaining the full dependence on the total pair-momentum and scattering geometry. We demonstrate that the resulting amplitudes differ significantly from conventional center-of-mass-frame results and, when applied to heavy-light quark scattering in the quark-gluon plasma (QGP), lead to 25-40% corrections to heavy-quark drag coefficients at low momenta, thereby removing a significant source of theoretical uncertainty in extracting the QGP transport properties with heavy-quark probes.
