LHC 能区大系统和小系统的涨落、关联和集体流

在相对论重离子碰撞领域, 高能量 Au+Au 和 Pb+Pb 等核核碰撞所产生的QGP系统被称为“大系统”, 而LHC和RHIC能区 p+Pb, d+Au 和 p+p 等碰撞所产生的系统被称为“小系统”。在不同的碰撞系统和碰撞能区，末态粒子的关联和集体流均被广泛的测量和关注。它们揭示了系统的初态涨落，集体运动，输运性质和相变等重要物理信息。本申请项目将围绕 LHC 能区大系统和小系统的涨落、关联和集体流这个课题在以下两个方面进行研究：1）进一步发展 iEBE-VISHNU 的数值模拟，研究和预言 LHC 能区5.02 A TeV Pb+Pb 碰撞的集体流和初态涨落；2) 利用不同的理论模型研究和预言 ７TeV 和 13 TeV p+p 碰撞所产生的小系统的末态粒子关联，集体流及非流效应。此外，我们还将系统的研究不同碰撞能量、不同尺度下大系统和小系统的局域热平衡及流体力学的适用范围。

In the community of relativistic heavy ion physics, the QGP systems created in high energy nucleus-nucleus collisions are called “large systems”. In contrast, the systems created in high energy p+Pb，d+Au and p+p collisions at RHIC and the LHC are called “small systems”. For different colliding systems at various collision energies, final state correlations and collective flow are important observables, which reveal the information on initial state fluctuations, collective expansion, phase transitions and the transport properties of the hot QCD matter. This proposal focuses on fluctuations, correlations and collective flow in large and small systems at the LHC, which mainly cover the two following aspects: 1) further develop iEBE-VISHNU hybrid model, study and predict the collective flow in 5.02 A TeV Pb+Pb collisions, investigate the details of initial state fluctuations; 2) study and predict the 2-particle, 4-particle correlations, collective flow and non-flow in 7 and 13 TeV p+p collisions. We will also explore the local equilibrium and the applicability of hydrodynamics in large and small systems at different collision energies.