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Guo R, Li Y, Chen B. Machine Learning Approach to Analyze the Heavy Quark Diffusion Coefficient in Relativistic Heavy Ion Collisions. ENTROPY (BASEL, SWITZERLAND) 2023; 25:1563. [PMID: 37998255 PMCID: PMC10670119 DOI: 10.3390/e25111563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 11/17/2023] [Accepted: 11/17/2023] [Indexed: 11/25/2023]
Abstract
The diffusion coefficient of heavy quarks in a deconfined medium is examined in this research using a deep convolutional neural network (CNN) that is trained with data from relativistic heavy ion collisions involving heavy flavor hadrons. The CNN is trained using observables such as the nuclear modification factor RAA and the elliptic flow v2 of non-prompt J/ψ from the B-hadron decay in different centralities, where B meson evolutions are calculated using the Langevin equation and the instantaneous coalescence model. The CNN outputs the parameters, thereby characterizing the temperature and momentum dependence of the heavy quark diffusion coefficient. By inputting the experimental data of the non-prompt J/ψ(RAA,v2) from various collision centralities into multiple channels of a well-trained network, we derive the values of the diffusion coefficient parameters. Additionally, we evaluate the uncertainty in determining the diffusion coefficient by taking into account the uncertainties present in the experimental data (RAA,v2), which serve as inputs to the deep neural network.
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Affiliation(s)
- Rui Guo
- Data Science, Washington University, St. Louis, MO 63105, USA;
| | - Yonghui Li
- Department of Physics, Tianjin University, Tianjin 300354, China
| | - Baoyi Chen
- Department of Physics, Tianjin University, Tianjin 300354, China
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Zhang SL, Liao J, Qin GY, Wang E, Xing H. Unraveling gluon jet quenching through J/ψ production in heavy-ion collisions. Sci Bull (Beijing) 2023; 68:2003-2009. [PMID: 37563031 DOI: 10.1016/j.scib.2023.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/18/2023] [Accepted: 06/29/2023] [Indexed: 08/12/2023]
Abstract
Jet quenching has long been regarded as one of the key signatures for the formation of quark-gluon plasma in heavy-ion collisions. Despite significant efforts, the separate identification of quark and gluon jet quenching has remained as a challenge. Here we show that J/ψ in high transverse momentum (pT) region provides a uniquely sensitive probe of in-medium gluon energy loss since its production at high pT is particularly dominated by gluon fragmentation. Such gluon-dominance is first demonstrated for the baseline of proton-proton collisions within the framework of leading power non-relativistic quantum chromodynamics factorization formalism. We then use the linear Boltzmann transport model combined with hydrodynamics for the simulation of jet-medium interaction in nucleus-nucleus collisions. The satisfactory description of experimental data on both nuclear modification factor RAA and elliptic flow v2 reveals, for the first time, that the gluon jet quenching is the driving force for high pTJ/ψ suppression. This novel finding is further confirmed by the data-driven Bayesian analyses of relevant experimental measurements, from which we also obtain the first quantitative extraction of the gluon energy loss distribution in the quark-gluon plasma.
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Affiliation(s)
- Shan-Liang Zhang
- Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE), Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Southern Nuclear Science Computing Center, South China Normal University, Guangzhou 510006, China
| | - Jinfeng Liao
- Physics Department and Center for Exploration of Energy and Matter, Indiana University, Bloomington 47408, USA.
| | - Guang-You Qin
- Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China.
| | - Enke Wang
- Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE), Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Southern Nuclear Science Computing Center, South China Normal University, Guangzhou 510006, China.
| | - Hongxi Xing
- Key Laboratory of Atomic and Subatomic Structure and Quantum Control (MOE), Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Nuclear Science, Institute of Quantum Matter, South China Normal University, Guangzhou 510006, China; Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Southern Nuclear Science Computing Center, South China Normal University, Guangzhou 510006, China; Southern Center for Nuclear-Science Theory (SCNT), Institute of Modern Physics, Chinese Academy of Sciences, Huizhou 516000, China.
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Zhao W, Ke W, Chen W, Luo T, Wang XN. From Hydrodynamics to Jet Quenching, Coalescence, and Hadron Cascade: A Coupled Approach to Solving the R_{AA}⊗v_{2} Puzzle. PHYSICAL REVIEW LETTERS 2022; 128:022302. [PMID: 35089775 DOI: 10.1103/physrevlett.128.022302] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 08/02/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
Hydrodynamics and jet quenching are responsible for the elliptic flow v_{2} and suppression of large transverse momentum (p_{T}) hadrons, respectively, two of the most important phenomena leading to the discovery of a strongly coupled quark-gluon plasma in high-energy heavy-ion collisions. A consistent description of the hadron suppression factor R_{AA} and v_{2}, especially at intermediate p_{T}, however, remains a challenge. We solve this long-standing R_{AA}⊗v_{2} puzzle by including quark coalescence for hadronization and final state hadron cascade in the coupled linear Boltzmann transport-hydro model that combines concurrent jet transport and hydrodynamic evolution of the bulk medium. We illustrate that quark coalescence and hadron cascade, two keys to solving the puzzle, also lead to a splitting of v_{2} for pions, kaons, and protons in the intermediate p_{T} region. We demonstrate for the first time that experimental data on R_{AA}, v_{2}, and their hadron flavor dependence from low to intermediate and high p_{T} in high-energy heavy-ion collisions can be understood within this coupled framework.
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Affiliation(s)
- Wenbin Zhao
- Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China
| | - Weiyao Ke
- Physics Department, University of California, Berkeley, California 94720, USA
- Nuclear Science Division MS 70R0319, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Wei Chen
- School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tan Luo
- Instituto Galego de Física de Altas Enerxías IGFAE, Universidade de Santiago de Compostela, E-15782 Galicia-Spain
| | - Xin-Nian Wang
- Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079, China
- Nuclear Science Division MS 70R0319, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Zakharov BG. Medium modification of photon-tagged and inclusive jets in high-multiplicity proton-proton collisions. PHYSICAL REVIEW LETTERS 2014; 112:032301. [PMID: 24484134 DOI: 10.1103/physrevlett.112.032301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Indexed: 06/03/2023]
Abstract
We study modification of the photon-tagged and inclusive jets in pp collisions at sqrt[s]=7 TeV due to mini-quark-gluon plasma which can be produced in high multiplicity events. We show that for underlying events with dN(ch)/dη∼20-60 the medium effects lead to a considerable modification of the photon-tagged and inclusive jet fragmentation functions. For inclusive jets, the magnitude of the effect is surprisingly large. The effect is quite strong even for typical underlying events. We find that the spectrum of charged hadrons is suppressed by ∼35%-40% at p(T)∼5-10 GeV.
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Affiliation(s)
- B G Zakharov
- L.D. Landau Institute for Theoretical Physics, GSP-1, 117940, Kosygina street 2, 117334 Moscow, Russia
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Peralta-Ramos J, Calzetta E. Effective dynamics of a non-Abelian plasma out of equilibrium. Int J Clin Exp Med 2012. [DOI: 10.1103/physrevd.86.125024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abir R, Greiner C, Martinez M, Mustafa MG, Uphoff J. Soft gluon emission off a heavy quark revisited. Int J Clin Exp Med 2012. [DOI: 10.1103/physrevd.85.054012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Abir R, Greiner C, Martinez M, Mustafa MG. Generalization of Gunion-Bertsch formula for soft gluon emission. Int J Clin Exp Med 2011. [DOI: 10.1103/physrevd.83.011501] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Qin GY, Majumder A. Perturbative QCD description of heavy and light flavor jet quenching. PHYSICAL REVIEW LETTERS 2010; 105:262301. [PMID: 21231648 DOI: 10.1103/physrevlett.105.262301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Indexed: 05/30/2023]
Abstract
We present a successful description of the medium modification of light and heavy flavor jets within a perturbative-QCD-based approach. Only the couplings involving hard partons are assumed to be weak. The effect of the medium on a hard parton, per unit time, is encoded in terms of three nonperturbative, related transport coefficients which describe the transverse momentum squared gained, the elastic energy loss, and diffusion in elastic energy transfer. Scaling the transport coefficients with the temperature of the medium, we achieve a good description of the centrality dependence of the suppression and the azimuthal anisotropy of leading hadrons. Imposing additional constraints based on leading order (LO) hard thermal loop (HTL) effective theory leads to a worsening of the fit, implying the necessity of computing transport coefficients beyond LO HTL.
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Affiliation(s)
- Guang-You Qin
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
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Mannarelli M, Manuel C, González-Solís S, Strickland M. Jet energy loss in the quark-gluon plasma by stream instabilities. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.81.074036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Andersen JO, Strickland M, Su N. Gluon thermodynamics at intermediate coupling. PHYSICAL REVIEW LETTERS 2010; 104:122003. [PMID: 20366527 DOI: 10.1103/physrevlett.104.122003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Indexed: 05/29/2023]
Abstract
We calculate the thermodynamic functions of Yang-Mills theory to three-loop order using the hard-thermal-loop perturbation theory reorganization of finite temperature quantum field theory. We show that at three-loop order hard-thermal-loop perturbation theory is compatible with lattice results for the pressure, energy density, and entropy down to temperatures T approximately 2-3T{c}.
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Affiliation(s)
- Jens O Andersen
- Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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Mrówczyński S, Müller B. Quasilinear transport approach to equilibration of quark-gluon plasmas. Int J Clin Exp Med 2010. [DOI: 10.1103/physrevd.81.065021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Qin GY, Majumder A, Song H, Heinz U. Energy and momentum deposited into a QCD medium by a jet shower. PHYSICAL REVIEW LETTERS 2009; 103:152303. [PMID: 19905626 DOI: 10.1103/physrevlett.103.152303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2009] [Indexed: 05/28/2023]
Abstract
For a hard parton moving through a dense QCD medium, we compute self-consistently the energy loss and the fraction deposited into the medium due to showering and rescattering of the shower, assuming weak coupling between probe and medium. The same transport coefficients thus determine both the energy loss and its deposition into the medium. This allows a parameter free calculation of the latter once the former are computed or measured. We compute them for a weakly interacting medium. Assuming a short thermalization time for the deposited energy, we determine the medium's hydrodynamical response and obtain a conical pattern that is strongly enhanced by showering.
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Affiliation(s)
- G-Y Qin
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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