标题： QCD迹异常 显示英文标题

标题： The QCD trace anomaly

摘要： 在本简要报告中，我们将最近的次次领头阶硬热圈微扰理论（HTLpt）对QCD迹异常的预测与现有的格点数据进行比较。我们关注两种情况下的迹异常除以T^2：N_f=0和N_f=3。当使用规范尺度mu = 2 pi T的标准值时，我们发现对于杨-米尔斯理论（N_f=0），HTLpt与格点数据在T^2归一化的迹异常上的吻合开始于温度约为8 T_c的情况，而当包含夸克（N_f=3）时，吻合已经在温度高于2 T_c的情况下开始。在两种情况下，我们发现当温度非常高时，T^2归一化的迹异常随着温度的增加而增加，这与HTLpt的预测一致。 显示英文摘要

摘要： In this brief report we compare the predictions of a recent next-to-next-to-leading order hard-thermal-loop perturbation theory (HTLpt) calculation of the QCD trace anomaly to available lattice data. We focus on the trace anomaly scaled by T^2 in two cases: N_f=0 and N_f=3. When using the canonical value of mu = 2 pi T for the renormalization scale, we find that for Yang-Mills theory (N_f=0) agreement between HTLpt and lattice data for the T^2-scaled trace anomaly begins at temperatures on the order of 8 T_c while when including quarks (N_f=3) agreement begins already at temperatures above 2 T_c. In both cases we find that at very high temperatures the T^2-scaled trace anomaly increases with temperature in accordance with the predictions of HTLpt.