Directed flow of charm quarks as a witness of the initial strong magnetic field in ultra-relativistic heavy ion collisions
Directed flow of charm quarks as a witness of the initial strong magnetic field in ultra-relativistic heavy ion collisions
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DOI：
10.1016/j.physletb.2017.02.046
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发表时间：
2017-05-10
影响因子：
4.4
通讯作者：
Greco, V.
中科院分区：
文献类型：
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作者：
Das, Santosh K.;Plumari, S.;Greco, V.
超相对论重离子碰撞(HIC)产生非常强的初始磁场(右箭头上方的(B))，在反应平面上产生涡旋。右箭头上方的高(B)影响与由于右箭头上方的时变(B)所产生的电场而产生的大的法拉第电流相反的演化动力学。结果表明，与轻夸克相比，魅力夸克(CQS)的定向流动(v(1))要大得多，这主要是由于以下几个有利条件的结合：(1)与CQS的轻夸克形成时间标度不同，近似或等于0.1fm/c的tau(F)与(B)在右箭头上方达到最大值时的时间尺度相当；(Ii)CQS的动力学驰豫时间与QGP寿命相似，这有助于CQ在横向上保留从电磁场中拾取的初始冲击。在电荷交换下，这种效应也是奇怪的，这使得它与由于初始角动量守恒而产生的块状物质的涡度不同；同时由于它的质量，M-c>；>；Lambda(QCD)，应该不会与手征磁动力学混合。因此，CQS提供了关于HIC产生的磁场强度的非常重要和独立的信息。(三)2017年提交人(S)。爱思唯尔出版公司(Elsevier B.V.)
Ultra-relativistic Heavy-Ion Collision (HIC) generates very strong initial magnetic field ((B) over right arrow) inducing a vorticity in the reaction plane. The high (B) over right arrow influences the evolution dynamics that is opposed by the large Faraday current due to electric field generated by the time varying (B) over right arrow. We show that the resultant effects entail a significantly large directed flow (v(1)) of charm quarks (CQs) compared to light quarks due to a combination of several favorable conditions for CQs, mainly: (i) unlike light quarks formation time scale of CQs, tau(f) similar or equal to 0.1 fm/c is comparable to the time scale when (B) over right arrow attains its maximum value and (ii) the kinetic relaxation time of CQs is similar to the QGP lifetime, this helps the CQ to retain the initial kick picked up from the electromagnetic field in the transverse direction. The effect is also odd under charge exchange allowing to distinguish it from the vorticity of the bulk matter due to the initial angular momentum conservation; conjointly thanks to its mass, M-c >> Lambda(QCD), there should be no mixing with the chiral magnetic dynamics. Hence CQs provide very crucial and independent information on the strength of the magnetic field produced in HIC. (C) 2017 The Author(s). Published by Elsevier B.V.