"Figure 2.1" of "Azimuthal anisotropy at RHIC: The first and fourth harmonics."

$v_4$ with respect to the second harmonic event plane as a function of $p_T$ for the minimum bias Au+Au collisions. Background from secondary particles is expected to be less than 15%. Non-flow systematic uncertainties are approximately 20%. Fluctuations in initial geometry can lead to an effect of about a factor of 1.2 to 1.5.针对最小偏置金金（Au+Au）碰撞，以二次谐波事件平面为参照的四次谐波流$v_4$随横动量（transverse momentum，$p_T$）的变化关系。其中次级粒子本底预计小于15%，非流效应的系统不确定度约为20%，初始几何结构的涨落可带来约1.2至1.5倍的影响。