Probing the Effects of Strong Electromagnetic Fields with Charge-Dependent Directed Flow in Pb-Pb Collisions at the LHC.
Probing the Effects of Strong Electromagnetic Fields with Charge-Dependent Directed Flow in Pb-Pb Collisions at the LHC.
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利用电荷相关定向流探索 LHC 中 Pb-Pb 碰撞中强电磁场的影响。
DOI：
10.1103/physrevlett.125.022301
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发表时间：
2020
影响因子：
8.6
通讯作者：
Acharya S
中科院分区：
文献类型：
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作者：
Acharya S
第一次测量在大型强子对撞机的电荷相关的定向流（）相对于观众平面的铅铅碰撞。本文报道了横向动量区间和中心度为5%-40%和10%-40%的带电强子和介子的计算结果。正负电荷强子之差随赝快度的变化有一个正斜率，dΔv1/dη=[1.68±0.49（stat）±0.41（syst）]×10-4。对介子的同样测量得到正值dΔv1/dη=[4.9±1.7（stat）±0.6（syst）]×10-1，比带电强子的大3个数量级。这些测量可以为强电磁场和非中心重离子碰撞中产生的物质初始倾斜对轻（u，d和s）和重（c）夸克动力学的影响提供新的见解。带电强子和带电介子的能量密度之间的巨大差异可能反映了粲夸克和轻夸克对重离子碰撞早期动力学的不同敏感性。这些观测结果对最近的一些理论计算提出了挑战，这些理论计算预测了轻味强子和粲强子的负的和小一个数量级的值。
The first measurement at the LHC of charge-dependent directed flow () relative to the spectator plane is presented for Pb-Pb collisions at. Results are reported for charged hadrons andmesons for the transverse momentum intervalsandin the 5%–40% and 10%–40% centrality classes, respectively. The difference between the positively and negatively charged hadronhas a positive slope as a function of pseudorapidity, dΔv1/dη=[1.68±0.49(stat)±0.41(syst)]×10-4. The same measurement forandmesons yields a positive value dΔv1/dη=[4.9±1.7(stat)±0.6(syst)]×10-1, which is about 3 orders of magnitude larger than the one of the charged hadrons. These measurements can provide new insights into the effects of the strong electromagnetic field and the initial tilt of matter created in noncentral heavy ion collisions on the dynamics of light (u, d, and s) and heavy (c) quarks. The large difference between the observedof charged hadrons andmesons may reflect different sensitivity of the charm and light quarks to the early time dynamics of a heavy ion collision. These observations challenge some recent theoretical calculations, which predicted a negative and an order of magnitude smaller value offor both light flavor and charmed hadrons.