(Multiple) Hard Parton Interactions in Heavy-Ion Collisions
Klaus Reygers
备注：
7 pages, 4 figures, to appear in the proceedings of the first International Workshop on Multiple Partonic Interactions at the LHC "1st MPI@LHC", Perugia, Italy, 27-31 October, 2008
Multiple hard interactions of partons in the same p+p(\bar p) collision are a useful concept in the description of these collisions at collider energies. In particular, they play a crucial role for the understanding of the background (the so-called underlying event) in the reconstruction of jets. In nucleus-nucleus collisions multiple hard parton interactions and the corresponding production of mini-jets are expected to contribute significantly to the total particle multiplicity. In this article a brief overview of results on particle production at high-pT in proton-proton and nucleus-nucleus at RHIC will be given. Moreover, the observed centrality dependence of the charged particle multiplicity in Au+Au collisions will be discussed in light of multiple partonic interactions.
STAR's measurement of Long-range forward-backward multiplicity correlations as the signature of "dense partonic matter" in the Heavy Ion collisions at $\sqrt{s_{NN}}=$200 GeV.}
Photon structure studied at an Electron Ion Collider
未来的电子离子对撞机（EIC）将能够提供极化电子与质子和重离子在宽范围的质心能量（20 $\mathrm{GeV}$至140 $\mathrm{GeV}$）的碰撞，瞬时亮度为$10^{33} - 10^{34}$ cm $^{-2}$ s $^{-1}$。它的一个有前途的物理计划是研究准实光子的部分子结构。在准真实的光生事件中测量双喷流，可以有效地获得光子的基本部分子动力学。在本文中，我们讨论了标记分辨光子过程和测量双射流截面作为射流横向动量的函数在EIC的$0.01<x_γ^{rec}<1$范围内的可行性。它将被证明，在光子的非偏振和偏振的部分子分布可以被提取，并且部分子的味道可以被标记在EIC。
Hadron production in heavy ion collisions: Fragmentation and recombination from a dense parton phase
本文讨论了RHIC上重离子碰撞中强子的产生。我们认为，横动量为P_T2GeV的强子< 5 GeV are formed by recombination of partons from the dense parton phase created in central collisions at RHIC. We provide a theoretical description of the recombination process for P_T >.在P_T = 2GeV以下，我们的结果与纯统计描述相吻合.在高横动量下，强子的产生可以用微扰QCD的语言用部分子的碎裂来描述。我们给出了各种强子谱、比率和核抑制因子的数值结果。我们还讨论了各向异性流v_2，并给出了基于部分子相流的结果。我们的结果与在175 MeV和0.55c的径向流速下RHIC强子化过程中部分子相的存在是一致的。
Influence of the Nucleon Hard Partons Distribution on J/ΨSuppression in a GMC Framework
在Glauber Monte Carlo框架下，考虑核子中硬部分子的横向空间分布，采用EPS 09阴影参数化方法，分析了d+Au碰撞中$J/ψ$的核修正因子$R_{dAu}$.在考虑核子硬部分子分布的影响后，d+Au碰撞中$R_{dAu}$对$N_{coll}$的依赖性有明显的向上修正，而对$p_{T}$的修正不明显.理论计算结果与PHENIX的实验数据符合得很好。
We explore parton collisional effects on the conversion of geometry eccentricities into azimuthal anisotropies in Pb+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV using a multi-phase transport model. The initial eccentricity $\varepsilon_{n}$ (n = 2,3) and flow harmonics $v_{n}$ (n = 2,3) are investigated as a function of the number of parton collisions ($N_{coll}$) during the source evolution of partonic phase. It is found that partonic collisions leads to generate elliptic flow $v_{2}$ and triangular flow $v_{3}$ in Pb+Pb collisions. On the other hand, partonic collisions also result in an evo…
Using the string melting version of a multiphase transport model, we focus on the evolution of thermodynamic properties of the central cell of parton matter produced in Au$+$Au collisions ranging from 200 GeV down to 2.7 GeV. The temperature and chemical potentials have been calculated based on both Boltzmann and quantum statistics in order to locate their evolution trajectories in the QCD phase diagram. We demonstrate that the trajectories can depend on many physical factors, especially the finite nuclear thickness at lower energies. However, from the evolution of pressure anisotropy, only pa…
Generalized parton distributions (GPDs) are important nonperturbative functions that provide tomographic images of partonic structures of hadrons. We introduce a type of exclusive processes, to be referred to as single diffractive hard exclusive processes (SDHEPs). We discuss the necessary and sufficient conditions for SDHEPs to be factorized into GPDs. We demonstrate that the SDHEP is not only sufficiently generic to cover all known processes for extracting GPDs, but is also well motivated for the search of new processes for the study of GPDs. We examine the sensitivity of the SDHEP to the pa…
Three Predictions for Partonic Energy Loss from Light to Heavy Ion Collisions
CERN（欧洲核子研究组织）；Utrecht University（乌得勒支大学）；NIKHEF（荷兰高能物理研究所）；University of the Witwatersrand（威特沃特斯兰德大学）；National Institute for Theoretical and Computational Sciences（国家理论与计算科学研究所）；Quaid-i-Azam University（奎德-阿扎姆大学）；National Centre for Physics（国家物理中心）
Medium induced parton energy loss is not conclusively established neither in very peripheral heavy-ion collisions nor in proton-ion collisions. However, the standard interpretation of azimuthal momentum anisotropies in theses systems implies some partonic rescattering. The upcoming light-ion runs at the LHC provide a unique opportunity to search for parton energy loss in different systems of similar size. Here, we make predictions for the expected parton energy loss signal in the charged hadron spectra in a system size scan at LHC. We test a large set of model assumptions against the transvers…
Wounded parton scaling of multiplicities in ultra-relativistic light- and heavy-ion collisions
Institute of Nuclear Physics, Polish Academy of Sciences（波兰科学院核物理研究所）；AGH University of Kraków, Faculty of Physics and Applied Computer Science（克拉科夫AGH科技大学物理与应用计算机科学学院）
An improved linear Boltzmann transport model for hadron and jet suppression in ultrarelativistic heavy-ion collisions
Institute of Frontier and Interdisciplinary Science, Shandong University（山东大学前沿交叉科学研究院）；School of Nuclear Science and Technology, University of South China（南华大学核科学技术学院）；Institute of Particle Physics and Key Laboratory of Quark and Lepton Physics (MOE), Central China Normal University（华中师范大学粒子物理与夸克轻子物理教育部重点实验室）
