Coalescence and flow in ultrarelativistic heavy ion collisions
Coalescence and flow in ultrarelativistic heavy ion collisions
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DOI：
10.1103/physrevc.59.1585
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发表时间：
1998-09
影响因子：
3.1
通讯作者：
R. Scheibl;U. Heinz
中科院分区：
文献类型：
--
作者：
R. Scheibl;U. Heinz
采用密度矩阵方法描述并合过程，计算了氘核和反氘核的并合概率和不变动量谱。我们评估我们的表达式与流体动力学动机的参数化的源在冻结，实现快速集体扩张的碰撞区中形成的重离子碰撞。我们发现，聚结过程是由相同的长度的均匀性，可以从Hanbury Brown\char21{}Twiss（HBT）干涉提取。它们出现在绝对集群产量通过一个有效的体积因子，以及在一个量子力学的校正因子，占的内部结构的氘核集群。我们的分析提供了一个新的解释流行的唯象聚结模型中的参数和哈格多恩的模型在$\mathrm{pp}$碰撞的集群生产的有效重叠体积。使用源参数提取从最近的HBT分析的2 π相关性，我们成功地描述了氘核和反氘核生产数据从$\mathrm{Pb}+\mathrm{Pb}$碰撞在欧洲核子研究中心SPS测量的NA 44和NA 52合作。我们还证实了Polleri等人最近的发现，即核子和氘核横向质谱的不同测量斜率要求源的横向密度分布更接近于一个盒子而不是高斯形状。
Using a density matrix approach to describe the process of coalescence, we calculate the coalescence probabilities and invariant momentum spectra for deuterons and antideuterons. We evaluate our expressions with a hydrodynamically motivated parametrization for the source at freeze-out which implements rapid collective expansion of the collision zone formed in heavy ion collisions. We find that the coalescence process is governed by the same lengths of homogeneity which can be extracted from Hanbury Brown\char21{}Twiss (HBT) interferometry. They appear in the absolute cluster yield via an effective volume factor as well as in a quantum-mechanical correction factor which accounts for the internal structure of the deuteron cluster. Our analysis provides a new interpretation for the parameters in the popular phenomenological coalescence model and for the effective overlap volume in Hagedorn's model for cluster production in $\mathrm{pp}$ collisions. Using source parameters extracted from a recent HBT analysis of two-pion correlations, we successfully describe deuteron and antideuteron production data from $\mathrm{Pb}+\mathrm{Pb}$ collisions at the CERN SPS as measured by the NA44 and NA52 Collaborations. We also confirm the recent finding by Polleri et al. that the different measured slopes of nucleon and deuteron transverse mass spectra require a transverse density profile of the source which is closer to a box than to a Gaussian shape.