通讯机构：
[Gupta, Sourendu] T;Tata Inst Fundamental Res, Dept Theoret Phys, Homi Bhabha Rd, Mumbai 400005, Maharashtra, India.
会议名称：
28th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (Quark Matter)
会议时间：
NOV 04-09, 2019
会议地点：
Wuhan, PEOPLES R CHINA
会议主办单位：
[Gupta, Sourendu] Tata Inst Fundamental Res, Dept Theoret Phys, Homi Bhabha Rd, Mumbai 400005, Maharashtra, India.^[Mallick, Debasish;Mohanty, Bedangadas] HBNI, Natl Inst Sci Educ & Res, Sch Phys Sci, Jatni 752050, India.^[Mishra, Dipak K.] Bhabha Atom Res Ctr, Nucl Phys Div, Mumbai 400085, Maharashtra, India.^[Mohanty, Bedangadas] CERN, Expt Phys Dept, CH-1211 Geneva 23, Switzerland.^[Xu, Nu] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.^[Xu, Nu] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.^[Xu, Nu] Chinese Acad Sci, Inst Modern Phys, 509 Nanchang Rd, Lanzhou 730000, Gansu, Peoples R China.
关键词：
Quark-gluon Plasma;Fluctuations;Thermalization;QCD Critical Point
摘要：
Arguments for thermalization of the QCD matter created in high-energy nuclear collisions has dominantly come from the agreement of the measured yields of produced hadrons with those from statistical thermal models. Ideally for a thermalized system, in addition to mean, the higher orders of the moments of the multiplicity distribution of produced particles should also show agreement with thermal models. In this respect, simultaneously studying the moments of the event-by-event distributions of conserved quantities like net-baryon, net-strangeness and net-charge number is best suited. We present a systematic study of comparing the results from a thermal hadron resonance gas (HRG) model with data on higher moments of net-proton, net-kaon and net-charge distributions measured at RHIC beam energy scan program. The experimental acceptances in terms of rapidity and transverse momentum are used in the model calculations which also include resonance decay. For the first time, the HRG model results are found to explain the measurements up to third order of moment with a common temperature and baryonic chemical potential. These calculations have tested the thermal nature of produced net-particle distributions up to third order, thereby providing evidence for thermalization of the QCD matter formed in such high energy heavy-ion collisions.
作者机构：
Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China;College of Physical Science and Technology, Central China Normal University, Wuhan, China;Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, USA;[Kenji Fukushima] Department of Physics, The University of Tokyo, Tokyo, Japan;School of Physical Sciences, National Institute of Science Education and Research, HBNI, Jatni, India
通讯机构：
[Nu Xu] I;Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China<&wdkj&>College of Physical Science and Technology, Central China Normal University, Wuhan, China<&wdkj&>Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, USA
摘要：
We make a theoretical and experimental summary of the state-of-the-art status of hot and dense QCD matter studies on selected topics. We review the Beam Energy Scan program for the QCD phase diagram and present the current status of the search for the QCD critical point, particle production in high baryon density region, hypernuclei production, and global polarization effects in nucleus-nucleus collisions. The available experimental data in the strangeness sector suggests that a grand canonical approach in the thermal model at high collision energy makes a transition to the canonical ensemble behavior at low energy. We further discuss future prospects of nuclear collisions to probe properties of baryon-rich matter. Creation of a quark-gluon plasma at high temperature and low baryon density has been called the “Little-Bang” and, analogously, a femtometer-scale explosion of baryon-rich matter at lower collision energy could be called the “femto-nova”, which could possibly sustain substantial vorticity and a magnetic field for non-head-on collisions.
作者机构：
[Bzdak, Adam] AGH Univ Sci & Technol, Fac Phys & Appl Comp Sci, PL-30059 Krakow, Poland.;[Esumi, ShinIchi] Univ Tsukuba, Tomonaga Ctr Hist Universe, Tsukuba, Ibaraki 305, Japan.;[Koch, Volker; Xu, Nu] Lawrence Berkeley Natl Lab, Nucl Sci Div, Berkeley, CA 94720 USA.;[Liao, Jinfeng] Indiana Univ, Phys Dept, 2401 N Milo B Sampson Lane, Bloomington, IN 47408 USA.;[Liao, Jinfeng] Indiana Univ, CEEM, 2401 N Milo B Sampson Lane, Bloomington, IN 47408 USA.
通讯机构：
[Liao, Jinfeng] I;Indiana Univ, Phys Dept, 2401 N Milo B Sampson Lane, Bloomington, IN 47408 USA.;Indiana Univ, CEEM, 2401 N Milo B Sampson Lane, Bloomington, IN 47408 USA.
会议名称：
PRPLC
关键词：
Heavy ion collision;Beam energy scan;QCD phase diagram;Critical point;Chiral magnetic effect
摘要：
We review the present status of the search for a phase transition and critical point as well as anomalous transport phenomena in Quantum Chromodynamics (QCD), with an emphasis on the Beam Energy Scan program at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. We present the conceptual framework and discuss the observables deemed most sensitive to a phase transition, QCD critical point, and anomalous transport, focusing on fluctuation and correlation measurements. Selected experimental results for these observables together with those characterizing the global properties of the systems created in heavy ion collisions are presented. We then discuss what can be already learned from the currently available data about the QCD critical point and anomalous transport as well as what additional measurements and theoretical developments are needed in order to discover these phenomena. (c) 2020 Elsevier B.V. All rights reserved.
摘要：
轻子散射实验是探索核子与原子核结构的理想工具。中国电子离子对撞机(Electron Ion Collider in China,EicC)建议书设想在已开建的强流重离子加速器装置(High Intensity heavy ion Accelerator Facility,HIAF)的基础上,升级质子束流为20 GeV的极化束流,并建造2.8~5 GeV极化电子束流,从而实现质心系能量为15~ 20 GeV的双极化电子-离子对撞。EicC设计的亮度为(2~4)×10~(33) cm~(–2)·s~(–1),质子束流极化率达到70%,电子束流极化率达到80%。该装置除了能提供极化轻离子束流(例如:氦-3)外,也可产生非极化重离子束流(碳-12 ~铀- 238)。EicC将聚焦核子海夸克部分子结构、原子核物质结构与性质、奇特强子态三个方面的物理研究。高亮度、高精度的对撞机有助于精确地测量核子结构函数并对核子进行三维成像,揭示强相互作用的动力学规律;原子核部分子分布包括核子短程关联以及原子核介质效应同样是该提案的重要科学目标;EicC能区接近重味夸克产生阈值,在研究重味强子谱方面拥有低背景的独特优势,有助于发现研究新的奇特强子态。质子质量起源问题也可以通过重味矢量介子的产生来研究。为了完成上述物理目标,我们将利用最先进的探测器技术建造接近全立体角覆盖的EicC对撞机谱仪。在准备EicC白皮书的过程中,我们得到世界各国专家的支持。EicC的物理与已有的实验和美国即将建设的EIC中的物理项目相互补充。EicC的建成及运行有望引领前沿的中高能核物理研究,使我国在加速器和探测器先进技术等领域实现跨越式发展,为我国核物理与强子物理以及相关科学领域提供大型综合实验平台与人才培养基地。
作者机构：
[Shi, Shusu; Xu, Nu; Lin, Zi-Wei; Nayak, Kishora] Cent China Normal Univ, Key Lab Quark & Lepton Phys, MOE, Wuhan 430079, Hubei, Peoples R China.;[Shi, Shusu; Xu, Nu; Lin, Zi-Wei; Nayak, Kishora] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;[Xu, Nu] Chinese Acad Sci, Inst Modern Phys, Lanzhou, Gansu, Peoples R China.;[Lin, Zi-Wei] East Carolina Univ, Dept Phys, Greenville, NC 27858 USA.
通讯机构：
[Shi, Shusu] C;Cent China Normal Univ, Key Lab Quark & Lepton Phys, MOE, Wuhan 430079, Hubei, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.
摘要：
The rapidity-odd component of directed flow ( v1) of identified hadrons ( π±, K±, KS0, p, p¯, ϕ, Ξ, Ξ¯, Λ, Λ¯) and partons ( u, u¯, d, d¯, s, s¯) in Au+Au collisions at various beam energies ( sNN=7.7, 11.5, 14.5, 19.6, 27, 39, 54.4, 62.4, 200 GeV) is analyzed using a multiphase transport model. A data driven approach (inspired from the experimental analysis) is performed here to distinguish the transported and produced quarks which are found to have different directed flow values at various collision beam energies. The coalescence sum rule (number of constituent quark scaling) violation is observed at lower energies where hadronic matters dominate. The strange quark ( s) and ϕ meson slope ( dv1/dy) show a double sign change around 14.5 GeV unlike other partons and hadrons. It suggests that the strange quark is more sensitive to the softening of the equation of state.
作者机构：
Faculty of International Liberal Arts, Akita International University, Yuwa, Akita 010-1292, Japan;Bhabha Atomic Research Centre, Bombay, 400 085, India;Vinca Institute of Nuclear Science, University of Belgrade, Belgrade, 11000, Serbia;Institute of Physics, University of Belgrade, Belgrade, 11000, Serbia;Collider and Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973-5000, United States
期刊：
XXII DAE HIGH ENERGY PHYSICS SYMPOSIUM,2018年 203: 1-5 ISSN：0930-8989
通讯作者：
Xu, Nu
作者机构：
[Xu, Nu] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;[Xu, Nu] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;[Xu, Nu] Lawrence Berkeley Natl Lab, Nucl Sci Div, Berkeley, CA 94720 USA.
通讯机构：
[Xu, Nu] C;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.
会议名称：
22nd DAE-BRNS High Energy Physics (HEP) Symposium
会议时间：
DEC 12-16, 2016
会议地点：
Univ Delhi, Dept Phys & Astrophys, New Delhi, INDIA
会议主办单位：
Univ Delhi, Dept Phys & Astrophys
会议论文集名称：
XXII DAE High Energy Physics Symposium
摘要：
We report selected results from the first phase of the beam energy scan program (BES-I) at RHIC. During the BES-I program we have collected data from Au\(+\)Au collisions at the center of mass energy range from \(\sqrt{s_{NN}}=7.7\) to 200 GeV, corresponding to baryonic chemical potential of \(\mu _B\approx \) 420 MeV to 20 MeV, respectively.
作者机构：
[Luo, Xiaofeng; Xu, Nu] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;[Luo, Xiaofeng; Xu, Nu] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;[Luo, Xiaofeng] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA.;[Xu, Nu] Lawrence Berkeley Natl Lab, Div Nucl Sci, Berkeley, CA 94720 USA.
通讯机构：
[Luo, Xiaofeng] C;[Luo, Xiaofeng] U;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.;Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA.
关键词：
QCD critical point;Fluctuations and correlations;Relativistic heavy-ion collisions;Conserved charges
摘要：
Fluctuations of conserved quantities, such as baryon, electric charge, and strangeness number, are sensitive observables in relativistic heavy-ion collisions to probe the QCD phase transition and search for the QCD critical point. In this paper, we review the experimental measurements of the cumulants (up to fourth order) of event-byevent net-proton (proxy for net-baryon), net-charge and netkaon (proxy for net-strangeness) multiplicity distributions in Au+Au collisions at sNN~(1/2) = 7.7,11.5,14.5,19.6, 27, 39, 62.4, 200 GeV from the first phase of beam energy scan program at the relativistic heavy-ion collider (RHIC). We also summarize the data analysis methods of suppressing the volume fluctuations, auto-correlations, and the unified description of efficiency correction and error estimation. Based on theoretical and model calculations, we will discuss the characteristic signatures of critical point as well as backgrounds for the fluctuation observables in heavy-ion collisions. The physics implications and the future second phase of the beam energy scan (2019–2020) at RHIC will also be discussed.
摘要：
Open and hidden heavy-flavor physics in high-energy nuclear collisions are entering a new and exciting stage towards reaching a clearer understanding of the new experimental results with the possibility to link them directly to the advancement in lattice Quantum Chromo-Dynamics (QCD). Recent results from experiments and theoretical developments regarding open and hidden heavy-flavor dynamics have been debated at the Lorentz Workshop Tomography of the Quark-Gluon Plasma with Heavy Quarks, which was held in October 2016 in Leiden, The Netherlands. In this contribution, we summarize identified common understandings and developed strategies for the upcoming five years, which aim at achieving a profound knowledge of the dynamical properties of the quark-gluon plasma.
摘要：
One of the main purposes of heavy-ion collisions over a wide range of beam energy is to study the bulk properties of strong interaction matter and understand the Quantum Chromo Dynamics (QCD) phase diagram, which carries wealth of information of the phase transition and the possibly existing critical point of the strongly interacting system [1]. Such system exists as hadron gases at lower temperature and low baryon density. By increasing the temperature or density, the boundary of the hadrons disappears and the confined quarks move freely in the whole system. Figure 1 shows the sketched QCD phase-diagram [2]. The red-thick line is the empirical chemical freeze-out curve. Nucleon mass is indicated by the filled dot at T = 0 MeV. The black-thick line is the speculated first-order phase boundary between quark-gluon plasma (QGP) and hadronic phase, while the open square point is the endpoint of the first-order phase boundary [3]. Since at μ_B = 0 the transition from QGP to hadronic phase is a smooth cross-over [4], at larger baryonic-chemical potential, thermodynamically there must be a critical point which ends the first-order phase transition line. Utilizing different beam energy, one can reach different regions on the phase diagram. The coverage of RHIC beam energy scan (BES) program and FAIR (SIS100-300) are shown as thin-lines in the figure [5]. The corresponding μ_B range of the CSR program is also indicated in the figure. While BES program of RHIC-STAR is dedicated to approach the critical point [5] from the high energy side, it is then of highly scientific importance to approach the CP from the low energy up and covers the studies of the phase diagram in the hadron phase.
摘要：
Substantial experimental and theoretical efforts worldwide are devoted to explore the phase diagram of strongly interacting matter. At LHC and top RHIC energies, QCD matter is studied at very high temperatures and nearly vanishing net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was created at experiments at RHIC and LHC. The transition from the QGP back to the hadron gas is found to be a smooth cross over. For larger net-baryon densities and lower temperatures, it is expected that the QCD phase diagram exhibits a rich structure, such as a first-order phase transition between hadronic and partonic matter which terminates in a critical point, or exotic phases like quarkyonic matter. The discovery of these landmarks would be a breakthrough in our understanding of the strong interaction and is therefore in the focus of various high-energy heavy-ion research programs. The Compressed Baryonic Matter (CBM) experiment at FAIR will play a unique role in the exploration of the QCD phase diagram in the region of high net-baryon densities, because it is designed to run at unprecedented interaction rates. High-rate operation is the key prerequisite for high-precision measurements of multi-differential observables and of rare diagnostic probes which are sensitive to the dense phase of the nuclear fireball. The goal of the CBM experiment at SIS100 (\(\sqrt{s_{NN}}=\) 2.7--4.9 GeV) is to discover fundamental properties of QCD matter: the phase structure at large baryon-chemical potentials ( \(\mu_B > 500\) MeV), effects of chiral symmetry, and the equation of state at high density as it is expected to occur in the core of neutron stars. In this article, we review the motivation for and the physics programme of CBM, including activities before the start of data taking in 2024, in the context of the worldwide efforts to explore high-density QCD matter.
会议名称：
25th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
会议时间：
SEP 27-OCT 03, 2015
会议地点：
Sci Council Japan, Kobe, JAPAN
会议主办单位：
Sci Council Japan
关键词：
Heavy Flavor;Quarkonium;Transport;Nuclear Collision;Quark Gluon Plasma
摘要：
The strong interaction between heavy quarks and the quark gluon plasma makes the open and hidden charm hadrons be sensitive probes of the deconfinement phase transition in high energy nuclear collisions. Both the cold and hot nuclear matter effects change with the colliding energy and significantly influence the heavy quark and charmonium yield and their transverse momentum distributions. The ratio of averaged quarkonium transverse momentum square and the elliptic flow reveal the nature of the QCD medium created in heavy ion collisions at SPS, RHIC and LHC energies.
作者机构：
[Luo, Xiaofeng; Xu, Nu; He, Shu] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;[Luo, Xiaofeng; Xu, Nu; He, Shu] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;[Nara, Yasushi] Akita Int Univ, Akita 0101292, Japan.;[Esumi, ShinIchi] Univ Tsukuba, Ctr Integrated Res Fundamental Sci & Engn, Tsukuba, Ibaraki 305, Japan.;[Xu, Nu] Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA.
通讯机构：
[Luo, Xiaofeng] C;Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Peoples R China.;Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要：
We analyze the rapidity and transverse momentum dependence for the cumulants of the net-proton and net-baryon distributions in Au+Au collisions at root SNN = 5 GeV with a microscopic hadronic transport (JAM) model. To study the effects of mean field potential and softening of equation of state (EoS) on the fluctuations of net-proton (baryon) in heavy-ion collisions, the calculations are performed with two different modes. The softening of EoS is realized in the model by implementing the attractive orbit in the two-body scattering to introduce a reduction pressure of the system. By comparing the results from the two modes with the results from default cascade, we find the mean field potential and softening of EoS have strong impacts on the rapidity distributions (dN/dy) and the shape of the net-proton (baryon) multiplicity distributions. The net-proton (baryon) cumulants and their ratios calculated from all of the three modes are with similar trends and show significant suppression with respect to unity, which can be explained by the presence of baryon number conservations. It indicates that the effects of mean field potential and softening of EoS might be not the ingredients that are responsible to the observed strong enhancement in the most central Au+Au collisions at 7.7 GeV measured by the STAR experiment at RHIC. (C) 2016 The Authors. Published by Elsevier B.V.
摘要：
It is important to understand the strong external magnetic field generated at the very beginning of heavy ion collisions. We study the effect of the magnetic field on the anisotropic charmonium formation in Pb+Pb collisions at the LHC energy. The time dependent Schrodinger equation is employed to describe the motion of c (c) over bar pairs. We compare our model prediction of the non-collective anisotropic parameter v(2) of J/psi with CMS data at high transverse momentum. (C) 2015 The Authors. Published by Elsevier B.V.
摘要：
We present a systematic comparison between the recently measured cumulants of the net-proton distributions by STAR for 0-5% central Au + Au collisions at root S-NN = 7.7-200 GeV and two kinds of possible baseline measure, the Poisson and Binomial baselines. These baseline measures are assuming that the proton and anti-proton distributions independently follow Poisson statistics or Binomial statistics. The higher order cumulant net-proton data are observed to deviate from all the baseline measures studied at 19.6 and 27 GeV. We also compare the net-proton with net-baryon fluctuations in UrQMD and AMPT model, and convert the net-proton fluctuations to net-baryon fluctuations in AMPT model by using a set of formula. (C) 2014 Elsevier B.V. All rights reserved.
摘要：
We investigate with a transport approach the cold and hot nuclear matter effects on the charmonium transverse momentum distributions in relativistic heavy ion collisions. The newly defined nuclear modification factor rAA=〈pT2〉AA/〈pT2〉pp and elliptic flow v2 for J/ψ are sensitive to the nature of the hot medium and the thermalization of heavy quarks. From Super Proton Synchrotron (SPS) through Relativistic Heavy Ion Collider (RHIC) to Large Hadron Collider (LHC) colliding energies, we observe dramatic changes in the centrality dependence of rAA. We find that, at LHC energy, the finally observed charmonia are dominated by the regeneration from thermalized heavy quarks.
