论文标题
中型修饰的$ g \ to c \ bar {c} $分裂功能在BDMPS-Z形式主义中
The medium-modified $g\to c\bar{c}$ splitting function in the BDMPS-Z formalism
论文作者
论文摘要
Baier-Dokshitzer-Mueller-Peigné-Schiff和Zakharov的形式主义决定了QCD等离子体中Parton分裂的修改，这是由中诱导的Gluon辐射引起的。在这里，我们研究了这种BDMPS-Z形式主义中的夸克 - 夸克对的中等修饰。我们得出了一个紧凑的路径综合公式，该公式从与培养基的任意数量相互作用到$ 1/n_c^2 $扩展中的领先顺序的效果。 $ n = 1 $不透明度和马鞍点近似值的分析显示了两个现象：中等诱导的相对夸克的动量扩大了 - 抗夸克对动量，从而增加了不变的夸克质量 - 夸克 - anti-quark对，以及这种对成对的中等增强的产生。我们注意到，如果从培养基的平均动量转移与夸克质量相当，则两种效应在数值上都是很大的。在超忠实的重型离子碰撞中，这种情况满足了魅力夸克。因此，我们将数值分析集中在$ g \的介质修改为c \ bar {c} $上，尽管我们的推导同样适用于$ g \ to $ g \ to b \ bar {b} $，并将分裂成轻型夸张的夸克夸克 - anti-quark对。
The formalism of Baier-Dokshitzer-Mueller-Peigné-Schiff and Zakharov determines the modifications of parton splittings in the QCD plasma that arise from medium-induced gluon radiation. Here, we study medium-modifications of the gluon splitting into a quark--anti-quark pair in this BDMPS-Z formalism. We derive a compact path-integral formulation that resums effects from an arbitrary number of interactions with the medium to leading order in the $1/N_c^2$ expansion. Analyses in the $N=1$ opacity and the saddle point approximations reveal two phenomena: a medium-induced momentum broadening of the relative quark--anti-quark pair momentum that increases the invariant mass of quark--anti-quark pairs, and a medium-enhanced production of such pairs. We note that both effects are numerically sizeable if the average momentum transfer from the medium is comparable to the quark mass. In ultra-relativistic heavy-ion collisions, this condition is satisfied for charm quarks. We therefore focus our numerical analysis on the medium modification of $g\to c\bar{c}$, although our derivation applies equally well to $g\to b\bar{b}$ and to gluons splitting into light-flavoured quark--anti-quark pairs.
