论文标题
对重夸克动量扩散的磁性贡献的晶格研究
Lattice study of a magnetic contribution to heavy quark momentum diffusion
论文作者
论文摘要
放置在热QCD培养基中的重夸克会经历布朗运动，其特征是特定的运输系数。可以通过将它们扩展为$ t/m $来简化他们的决心，其中$ t $是温度，$ m $是沉重的夸克质量。扩展中的主要术语源自洛伦兹力的颜色 - 电动部分，而次要领先的顺序涉及颜色磁性部分。我们在$ t \ sim 1.2 ... 2.0 t _ {\ rm c}^{} $中测量QCD中的颜色 - 磁性2点相关器。采用多级技术和非扰动重新归一化，获得了良好的信号，并且可以估算其连续性外推。为相应光谱函数的形状进行建模，我们随后提取动量扩散系数$κ$。对于魅力（底部）夸克，磁性贡献将$ \ sim 30 \％$（$ 10 \％$）增加到电动机。同样的增加也适用于阻力系数$η$。顺便说一句，在NLO上计算了颜色磁光谱函数。
Heavy quarks placed within a hot QCD medium undergo Brownian motion, characterized by specific transport coefficients. Their determination can be simplified by expanding them in $T/M$, where $T$ is the temperature and $M$ is a heavy quark mass. The leading term in the expansion originates from the colour-electric part of a Lorentz force, whereas the next-to-leading order involves the colour-magnetic part. We measure a colour-magnetic 2-point correlator in quenched QCD at $T \sim 1.2 ... 2.0 T_{\rm c}^{ }$. Employing multilevel techniques and non-perturbative renormalization, a good signal is obtained, and its continuum extrapolation can be estimated. Modelling the shape of the corresponding spectral function, we subsequently extract the momentum diffusion coefficient, $κ$. For charm (bottom) quarks, the magnetic contribution adds $\sim 30\%$ ($10\%$) to the electric one. The same increases apply also to the drag coefficient, $η$. As an aside, the colour-magnetic spectral function is computed at NLO.
