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Nuclear Science and Techniques 2023年第4期34卷 175-184页

作者： Kui Xiao Peng-Cheng Li Yong-Jia Wang Fu-Hu Liu Qing-Feng Li State Key Laboratory of Quantum Optics and Quantum Optics Devices and Collaborative Innovation Center of Extreme Optics Institute of Theoretical PhysicsShanxi UniversityTaiyuan 030006China School of Science Huzhou UniversityHuzhou 313000China School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Institut für Theoretische Physik Goethe Universität FrankfurtFrankfurt am Main 60438Germany Institute of Modern Physics Chinese Academy of ScienceLanzhou 730000China

In this study, the rapidity distribution, collective flows, and nuclear stopping power in ^(197)Au+^(197)Au collisions at intermediate energies were investigated using the ultrarelativistic quantum molecular dynamics(UrQMD) model with GEMINI++ code. The UrQMD model was adopted to simulate the dynamic evolution of heavy-ion collisions, whereas the GEMINI++ code was used to simulate the decay of primary fragments produced by UrQMD. The calculated results were compared with the INDRA and FOPI experimental data. It was found that the rapidity distribution, collective flows, and nuclear stopping power were affected to a certain extent by the decay of primary fragments, especially at lower beam energies. Furthermore, the experimental data of the collective flows and nuclear stopping power at the investigated beam energies were better reproduced when the sequential decay effect was included.

关键词： heavy-ion collisions Sequential decay effect Collective flow Nuclear stopping power

Recent development of hydrodynamic modeling in heavy-ion collisions

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Nuclear Science and Techniques 2020年第12期31卷 88-121页

作者： Chun Shen Li Yan Department of Physics and Astronomy Wayne State UniversityDetroitMI 48201USA RIKEN BNL Research Center Brookhaven National LaboratoryUptonNY 11973USA Key Laboratory of Nuclear Physics and ion-Beam Application(MOE) Institute of Modern PhysicsFudan University220 Handan RoadShanghai 200433China

We present a concise review of the recent development of relativistic hydrodynamics and its applications to heavy-ion collisions.Theoretical progress on the extended formulation of hydrodynamics toward out-ofequilibrium systems is addressed,with emphasis on the socalled attractor solution.Moreover,recent phenomenological improvements in the hydrodynamic modeling of heavy-ion collisions with respect to the ongoing beam energy scan program,the quantitative characterization of transport coefficients in three-dimensionally expanding quark–gluon plasma,the fluid description of small colliding systems,and certain other interdisciplinary connections are discussed.

关键词： heavy-ion collisions Hydrodynamics QCD

Medium modifications of girth distributions for inclusive jets and Z0+jets in relativistic heavy-ion collisions at the LHC

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Chinese Physics C 2021年第2期45卷 426-432页

作者：鄢君陈时勇代巍张本威王恩科 Key Laboratory of Quark&Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China School of Mathematics and Physics China University of GeosciencesWuhan 430074China Institute of Quantum Matter South China Normal UniversityGuangzhou 510006China

In this paper,we investigate the medium modifications of girth distributions for inclusive jets and Z^0 tagged jets with a small radius( R=0.2 )in Pb+Pb collisions with √s==2.76 TeV at the LHC.The partonic spectra in the initial hard scattering of elementary collisions are obtained by an event generator POWHEG+PYTHIA,which matches the next-to-leading order(NLO)matrix elements with parton showering,and the energy loss of a fast parton traversing the hot/dense QCD medium is calculated by Monte Carlo simulation within the higher-twist formalism of jet quenching in heavy-ion collisions.We present the model calculations of event normalized girth distributions for inclusive jets in p+p and Pb+Pb collisions at √s=2.76 TeV,which give good descriptions of ALICE measurements.It is shown that the girth distributions of inclusive jets in Pb+Pb are shifted to lower girth regions relative to those in p+p.Thus,the nuclear modification factor of girth distributions for inclusive jets is larger than unity at small girth regions and smaller than unity at large girth regions.This behavior results from softer fragments inside a jet as well as the fraction alteration of gluon/quark initiated jets in heavy-ion collisions.We further predict the girth distributions for Z^0 boson tagged jets in Pb+Pb collisions at √s=2.76 TeV and demonstrate that the medium modification on girth distributions for Z^0 tagged jets is less pronounced compared to that for inclusive jets because the dominant components of Z^0 tagged jets are quark-initiated jets.

关键词： heavy-ion collisions jet quenching quark gluon plasma jet substructure

Symmetry energy from neutron-rich fragments in heavy-ion collisions,and its dependence on incident energy,and impact parameters

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Chinese Physics C 2013年第2期37卷 19-25页

作者：马春旺宋恒利普洁张同林张莎王闪闪赵新丽陈丽 Department of Physics Henan Normal University Department of Nuclear Physics Shanghai Institute of Applied Physics

The yields of fragments produced in the ^60Ni＋ ^12C reactions at 80 A and 140 A MeV, and with maximum impact parameters of 1.5, 2 and 7.3 fm at 80 A MeV are calculated by the statistical abrasion-ablation model. The yields of fragments are analyzed by the isobaric yield ratio （IYR） method to extract the coefficient of symmetry energy to temperature （asym/T ）. The incident energy is found to influence asym/T very little. It’s found that asym/T of fragments with the same neutron-excess I = N-Z increases when A increases, while asym/T of isobars decreases when A increases. The asym/T of prefragments is rather smaller than that of the final fragments, and the asym/T of fragments in small impact parameters is smaller than that of the larger impact parameters, which both indicate that asym/T decreases when the temperature increases. The choice of the reference IYRs is found to have influence on the extracted a sym /T of fragments, especially on the results of the more neutron-rich fragments. The surface-symmetry energy coefficient （bs/T ） and the volume-symmetry energy coefficient （bv/T） are also extracted, and the bs/bv is found to coincide with the theoretical results.

关键词： symmetry energy isobaric yield ratio neutron-rich nucleus heavy-ion collisions

Investigation of experimental observables in search of the chiral magnetic effect in heavy-ion collisions in the STAR experiment

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Chinese Physics C 2022年第1期46卷 129-145页

作者： Subikash Choudhury Xin Dong Jim Drachenberg James Dunlop ShinIchi Esumi 冯毅程 Evan Finch 胡昱 Jiangyong Jia Jerome Lauret Wei Li 廖劲峰林裕富 Mike Lisa Takafumi Niida Robert Lanny Ray Masha Sergeeva 申迪宇施舒哲 Paul Sorensen 唐爱洪 Prithwish Tribedy Gene Van Buren Sergei Voloshin 王福强王钢徐浩洁徐之湾 Nanxi Yao 赵杰 Fudan University Shanghai200433 Lawrence Berkeley National Laboratory BerkeleyCalifornia 94720 Abilene Christian University AbileneTexas 79699 Brookhaven National Laboratory UptonNew York 11973 University of Tsukuba TsukubaIbaraki 305-8571 Purdue University West LafayetteIndiana 47907 Southern Connecticut State University New HavenConnecticut 06515 State University of New York Stony BrookNew York 11794 Rice University HoustonTexas 77251 Physics Department and Center for Exploration of Energy and Matter Indiana University2401 N Milo B.Sampson LaneBloomingtonIN 47408 College of Physics and Technology Guangxi Normal UniversityGuilin541004 Central China Normal University WuhanHubei 430079 Ohio State University ColumbusOhio 43210 University of Texas AustinTexas 78712 University of California Los AngelesCalifornia 90095 Department of Physics McGill University3600 University StreetMontrealQCH3A 2T8 Wayne State University DetroitMichigan 48201 Huzhou University HuzhouZhejiang 313000

The chiral magnetic effect(CME)is a novel transport phenomenon,arising from the interplay between quantum anomalies and strong magnetic fields in chiral systems.In high-energy nuclear collisions,the CME may survive the expansion of the quark-gluon plasma fireball and be detected in experiments.Over the past two decades,experimental searches for the CME have attracted extensive interest at the Relativistic heavy ion Collider(RHIC)and the Large Hadron Collider(LHC).The main goal of this study is to investigate three pertinent experimental approaches:the$\gamma$correlator,the R correlator,and the signed balance functions.We exploit simple Monte Carlo simulations and a realistic event generator(EBE-AVFD)to verify the equivalence of the core components among these methods and to ascertain their sensitivities to the CME signal and the background contributions for the isobar collisions at the RHIC.

关键词： chiral magnetic effect anisotropic flow heavy-ion collisions quark-gluon plasma

The effect of hadronic scatterings on the measurement of vector meson spin alignments in heavy-ion collisions

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Chinese Physics C 2021年第5期45卷 105-112页

作者：申迪宇陈金辉林子威 Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Bejjing 100049China Institute of Modern Physics and Key Laboratory of Nuclear Physics and lon-beam Application(MOE) Fudan UniversityShanghai 200433China Key Laboratory of Quarks and L epton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China Department of Physics East Carolina UniversityGreenvilleNorth Carolina 27858USA

Spin alignments of vector mesons and hyperons in relativistic heavy-ion collisions have been proposed as signals of global polarization.The STAR experiment first observed the ∧ polarization.Recently,the ALICE collaboration measured the transverse momentum {PT) and the collision centrality dependence of K*,and Φ spin alignments during Pb-Pb collisions at 1/2sNN=2.76 TeV.A large signal is observed in the low pT region of mid-central collisions for K*,while the signal is much smaller for Φ,and these have not been understood yet.Since vector mesons have different lifetimes and their decay products have different scattering cross sections,they suffer from different hadronic effects.In this paper,we study the effect of hadronic interactions on the spin alignment of K*,Φ,and p mesons in relativistic heavy-ion collisions with a multi-phase transport model.We find that hadronic scatterings lead to a deviation of the observed spin alignment matrix element p00 away from the true value for p and K*mesons(with a bigger effect on p) while the effect is negligible for the Φ meson.The effect depends on the kinematic acceptance:the observed p00 value is lower than the true value when the pseudorapidity(η) coverage is small,while there is little effect when the η coverage is large.Hence,this study provides valuable information to understand the vector meson spin alignment signals observed during the experiments.

关键词： heavy-ion collisions global polarization vector meson spin alignment acceptance effect hadronic scatterings

Charge-dependent correlations in heavy-ion collisions from stochastic hydrodynamics

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Communications in Theoretical Physics 2020年第11期72卷 80-86页

作者： Gui-Rong Liang Miao Li School of Physics and Astronomy Sun Yat-Sen UniversityZhuhai519082China Department of Physics Southern University of Science and TechnologyShenzhen 518055GuangdongChina

Charge-dependent correlations from both background and charge separation contribute to experimental observables in heavy-ion collisions.In this paper,we use stochastic hydrodynamics to study background charge asymmetry due to fluctuations.Using the rapidity-dependent correlation and a simple ansatz for particle distributions,we find a fluctuation-induced correlation to provide a type of background F-correlation.Experimental data for Au+Au collisions at(sNN)1/2=200 GeV are compared.We also make predictions for F-correlations in isobar collisions.Combining this with our previous chiral magnetic effect results,we obtainδ-correlations for collisions in the three types of system.Computations from our model show an almost identical background with less than 2%difference for isobars,but roughly 10%difference for their charge separations.In combination with our earlier works,we provide a consistent method of calculating both the chiral magnetic effect and the charged background in the context of stochastic hydrodynamics.

关键词： stochastic hydrodynamics heavy-ion collisions background charge fluctuations isobar collisions charge-dependent correlations

Efficiency corrections for mutually inclusive variables and particle identification effect for mixed-cumulants in heavy-ion collisions

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Chinese Physics C 2021年第10期45卷 58-68页

作者： Arghya Chatterjee Toshihiro Nonaka ShinIchi Esumi 罗晓峰 Key Laboratory of Quark&Lepton Physics(MOE)and Institute of Particle Physics Central China Normal UniversityWuhan 430079China Tomonaga Center for the History of the Universe University of TsukubaIbaraki 305Japan

Mix-cumulants of conserved charge distributions are sensitive observables for probing properties of the QCD medium and phase transition in heavy-ion collisions.To perform precise measurements,efficiency correction is one of the most important step.In this study,using the binomial efficiency model,we derive efficiency correction formulas for mutually exclusive and inclusive variables.The UrQMD model is applied to verify the validity of these formulas for different types of correlations.Furthermore,we investigate the effect of the multiplicity loss and contamination emerging from the particle identifications.This study provides important steps toward future measurements of mixed-cumulants in relativistic heavy-ion collisions.

关键词： QCD critical point heavy-ion collisions quark-gluon plasma fluctuations and correlations

A flow paradigm in heavy-ion collisions

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Chinese Physics C 2018年第4期42卷 1-43页

作者： Li Yan Department of Physics Mc Gill University

The success of hydrodynamics in high energy heavy-ion collisions leads to a flow paradigm, to understand the observed features of harmonic flow in terms of the medium collective expansion with respect to initial state geometrical properties. In this review, we present some essential ingredients in the flow paradigm, including the hydrodynamic modeling, the characterization of initial state geometry and the medium response relations. The extension of the flow paradigm to small colliding systems is also discussed.

关键词： heavy-ion collisions hydrodynamics harmonic flow

Transverse mass distributions in central heavy-ion collisions at high energies

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Chinese Physics C 2011年第4期35卷 355-362页

作者：谢文杰杨德王翠平王志刚 Department of Physics Yuncheng University Department of Mathematics and Physics Hebei Institute of Architecture and Civil Engineering Institute of High Energy Physics CAS

The transverse mass spectra of protons, pions, kaons, Lambda and Antilambda produced in central nucleus-nucleus collisions at high energies are described by using one-temperature and two-temperature emission pictures. The calculated results are compared and found to be in good agreement with the experimental data of the E895, E866 and E917 Collaborations measured in central Au-Au collisions at the Alternating Gradient Synchrotron （AGS） energies and the NA49 Collaboration measured in central Pb-Pb collisions at the Super Proton Synchrotron （SPS） energies. It is demonstrated that the transverse mass distributions of protons, kaons, Lambda and Antilambda, except for Lambda hyperons produced in central Pb-Pb collisions at 158 A GeV, can be described by using the one-temperature emission picture, and for pions, we need to use the two-temperature emission picture.

关键词： transverse mass spectra one-temperature emission picture two-temperature emission picture heavy-ion collisions