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arXiv 1508.04543hep-lathep-ph
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重夸克动量扩散系数的非微扰估计

A non-perturbative estimate of the heavy quark momentum diffusion coefficient

A. Francis, O. Kaczmarek, M. Laine, T. Neuhaus, H. Ohno

摘要:

我们估计了在1.5Tc温度下纯SU(3)等离子体中重夸克的动量扩散系数。在一系列扩展到192 ^3 *48的晶格上进行的大规模蒙特卡罗模拟使我们能够对所谓的色电时间相关器进行连续外推。外推相关器的分析与相应的光谱函数的理论动机模型的帮助下。我们发现了非零输运系数的证据,并结合反映模型假设的系统不确定性,得到了kappa =(1.8 - 3.4)T^3。这意味着表征重夸克适应流体动力学流动的时间尺度的“拖曳系数”为(1.8 - 3.4)(Tc/T)^2(M/1.5GeV)fm/c,其中M是重夸克的动力学质量。结果适用于底夸克,并具有较大的系统不确定性,适用于粲夸克。

英文摘要:

We estimate the momentum diffusion coefficient of a heavy quark within a pure SU(3) plasma at a temperature of about 1.5Tc. Large-scale Monte Carlo simulations on a series of lattices extending up to 192^3*48 permit us to carry out a continuum extrapolation of the so-called colour-electric imaginary-time correlator. The extrapolated correlator is analyzed with the help of theoretically motivated models for the corresponding spectral function. Evidence for a non-zero transport coefficient is found and, incorporating systematic uncertainties reflecting model assumptions, we obtain kappa = (1.8 - 3.4)T^3. This implies that the "drag coefficient", characterizing the time scale at which heavy quarks adjust to hydrodynamic flow, is (1.8 - 3.4) (Tc/T)^2 (M/1.5GeV) fm/c, where M is the heavy quark kinetic mass. The results apply to bottom and, with somewhat larger systematic uncertainties, to charm quarks.

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