不透明度虚部,强子物质流与单极化不对称

考虑不透明度虚部的作用，讨论了单极化不对称性，在程涵近似下，发现极化靶内部的强子物质流和不透明度虚部是导致单极化不对称的重要原因。     

Track matching study from TPC to PHOS in ALICE

We present a study for matching charged tracks reconstructed from the ALICE tracking detectors with the clusters measured in the photon spectrometer. Matching efficiency and contaminations due to wrong matches have been deduced for charged pions and muons. For electrons, the effect of the material in front of PHOS is discussed.     

大型强子对撞机上的大型重离子碰撞实验

探索物质微观结构和新的物质形态始终是人类认识物质世界的基本规律的一个重要组成部分。随着物理学的发展,人类对物质的微观结构的认识逐步深入,先后认识到：物质世界是由原子组成的,     

质子—反质子有效相互作用半径的能量依赖

利用程函近似方法，在能量２３．５ＧｅＶ，６２ＧｅＶ，５４６ＧｅＶ和１．８ＴｅＶ下，计算了质子反质子的有效相互作用半径，结果表明，质子－反质子的有效相互作用半径并非随ｌｏｇ√ｓ线性增大，而是随着能量的增大逐渐趋于饱和。     

质子－反质子有效相互作用半径的能量依赖

利用程函近似方法,在能量２３．５ＧｅＶ,６２ＧｅＶ,５４６ＧｅＶ和１．８ＴｅＶ下,计算了质子－反质子的有效相互作用半径．结果表明：质子－反质子的有效相互作用半径并非随ｌｏｇｓ线性增大,而是随着能量的增大逐渐趋于饱和     

Energy Loss of Charm Quark Observed via Dimuon Production in Pb-Pb Collisions at √snn = 5.5 TeV

Based on the HVQMNR model of heavy flavour production and the BDMPS approach on parton energy loss, we have investigated the energy loss effect of charm quark on （di）muon spectra in forward rapidity region covered by ALICE forward muon spectrometer in Pb＋Pb collisions at c.m. energy √snn= 5.5 TeV. Results show that （di）muon spectra are very sensitive to the charm quark energy loss and can provide valuable information on the energy loss of heavy flavours.     

Study of the photon identification efficiency with ALICE photon spectrometer

The efficiency for the detection and identification of photons with the ALICE PHOton Spectrometer PHOS has been studied with the Monte-Carlo generated data. In particular, the influence on the efficiency of the PHOS-module edge-effect and of the material in front of PHOS have been examined.     

Estimation of the chiral magnetic effect considering the magnetic field response of the QGP medium

The magnetic field plays a major role in searching for the chiral magnetic effect in relativistic heavy-ion collisions. If the lifetime of the magnetic field is too short, as predicted by simulations of the field in vacuum, the chiral magnetic effect will be largely suppressed. However, the lifetime of the magnetic field will become longer when the QGP medium response is considered. We give an estimate of the effect, especially considering the magnetic field response of the QGP medium, and compare it with the experimental results for the background-subtracted correlator H at RHIC and LHC energies. The results show that our method explains the experimental results better at the top RHIC energy than at the LHC energy.     

相对论重离子碰撞手征电荷分离效应的研究

相对论重离子碰撞的拓扑荷作用破坏作用平面两侧不同手征性的夸克数目的平衡,从而引起P和CP破坏特征。本工作主要分析RHIC和LHC能区的手征电荷分离作用,分析手征电荷分离随碰撞中心度、碰撞能量和核屏蔽等依赖关系。并未发现手征电荷分离效应与碰撞能量大小有非常紧密的依赖关系,但发现核屏蔽效应对手征电荷分离有重要的影响,与不考虑屏蔽效应相比,考虑屏蔽效应会使手征分离效应明显压低,由于屏蔽效应出现,使得a₊₊（a_--）的分布与a_+-（a_-+）分布并不对称。并且还发现手征分离效应主要发生在碰撞参量较大的周边碰撞,越接近中心碰撞,手征分离效应几乎可以忽略。The topological charge interactions in relativistic heavy ion collisions cause quark chirality imbalance, resulting in charge separation under the strong magnetic field and local P and CP violation. In this paper, the chiral charge separation at RHIC and LHC energies is systematically analyzed as functions of the collision centrality, the collision energy and the nuclear shielding factor. It is found that there is not a very close dependence of the chiral charge separation effect on the collision energies, but that has an important dependence on nuclear shielding factor. Compared with the non-shielding effect, the shielding effect can reduce the chiral separation effect obviously. Due to the shielding effect, the distribution of a₊₊(a_--) and the distribution of a_+-(a_-+) are asymmetric. One also finds that chiral separation effect, which is almost negligible when more close to the central collision, occurs mainly in the peripheral collision for larger impact parameter.