论文标题
射流从线性化流体力学唤醒
Jet Wake from Linearized Hydrodynamics
论文作者
论文摘要
我们探讨了如何改善构成颗粒的杂种模型描述，该描述起源于重离子碰撞叶片在Quark-Gluon等离子体（QGP）的液滴中产生的射流，该射流在Bjorken Flow上使用线性化的流体动力学传播。杂种模型描述的喷气能量和动量损失变为采购线性流体动力学的电流。通过以数值方式求解线性化的流体动力方程，我们研究了QGP动态不断发展的液滴中的唤醒的发展，研究粘度的效果，仔细检查能量摩尔植物的保存并检查线性近似的有效性。我们发现线性化的流体力学在粘性情况下效果更好，因为扩散模式抑制了射流产生的能量摩托扰动。我们通过使用Cooper-Frye处方来计算从射流唤醒产生的颗粒的分布，并发现在线性化的流体动力学和混合模型中，横向动量光谱和方位角角度的颗粒分布相似。它们的正常化是不同的，因为由于声音模式，线性化流体动力学分析中的动量 - 长度分布更加分布。由于Bjorken流量没有横向膨胀，因此我们通过使用局部增压器将其添加到Cooper-Frye公式中来探索横向流的效果。在以这种方式包含横向流动的影响之后，横向动量光谱变得更加困难：与混合模型相比，产生的横向动量大于$ 2 $ GEV的颗粒要大于$ 2 $ GEV。尽管我们将这种分析推迟在喷气式蒙特卡洛（Jet Monte Carlo）进行定量比较，但我们对喷气唤醒如何通过计算两个示例可观察到的代理来修改Jet可观测值的定性感觉：在不同的开放角度中恢复的损失能量：损失的能量，以及碎片功能。我们发现，添加带有横向流动效应的线性化流体动力学可以通过与数据进行比较的方式来改善混合模型中射流唤醒的描述。我们的研究阐明了改善杂种模型中唤醒描述的途径，强调需要考虑到横向流的影响以及时空速度迅速性对粒子产生的能量摩托扰动的影响。
We explore how to improve the hybrid model description of the particles originating from the wake that a jet produced in a heavy ion collision leaves in the droplet of quark-gluon plasma (QGP) through which it propagates, using linearized hydrodynamics on a background Bjorken flow. Jet energy and momentum loss described by the hybrid model become currents sourcing linearized hydrodynamics. By solving the linearized hydrodynamic equations numerically, we investigate the development of the wake in the dynamically evolving droplet of QGP, study the effect of viscosity, scrutinize energy-momentum conservation, and check the validity of the linear approximation. We find that linearized hydrodynamics works better in the viscous case because diffusive modes damp the energy-momentum perturbation produced by the jet. We calculate the distribution of particles produced from the jet wake by using the Cooper-Frye prescription and find that both the transverse momentum spectrum and the distribution of particles in azimuthal angle are similar in shape in linearized hydrodynamics and in the hybrid model. Their normalizations are different because the momentum-rapidity distribution in the linearized hydrodynamics analysis is more spread out, due to sound modes. Since the Bjorken flow has no transverse expansion, we explore the effect of transverse flow by using local boosts to add it into the Cooper-Frye formula. After including the effects of transverse flow in this way, the transverse momentum spectrum becomes harder: more particles with transverse momenta bigger than $2$ GeV are produced than in the hybrid model. Although we defer implementing this analysis in a jet Monte Carlo, as would be needed to make quantitative comparisons to data, we gain a qualitative sense of how the jet wake may modify jet observables by computing proxies for two example observables: the lost energy recovered in a cone of varying open angle, and the fragmentation function. We find that linearized hydrodynamics with transverse flow effects added improves the description of the jet wake in the hybrid model in just the way that comparison to data indicates is needed. Our study illuminates a path to improving the description of the wake in the hybrid model, highlighting the need to take into account the effects of both transverse flow and the broadening of the energy-momentum perturbation in spacetime rapidity on particle production.
