Transport Model

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Y. G. - One of the best experts on this subject based on the ideXlab platform.

  • extracting jet Transport parameter hat q from a multiphase Transport Model
    European Physical Journal A, 2020
    Co-Authors: Fengchu Zhou, Y. G.
    Abstract:

    Within a multiphase Transport Model with a string-melting scenario, the jet Transport parameter $$\hat{q}$$ is extracted in Au+Au collisions at $$\sqrt{s_{NN} } $$= 200 GeV and Pb+Pb collisions at $$\sqrt{s_{NN} } $$= 2.76 TeV. The jet Transport parameter $$\hat{q}$$ is a key parameter in jet-quenching phenomena, which depends not only on the temperature of the QCD medium but also on jet energy. We observe that $$\hat{q}$$ increases with increasing of the jet energy for both the partonic phase and the hadronic phase. The energy and path length dependences of $$\hat{q}$$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet Transport parameter $$\hat{q}$$ and dijet transverse momentum asymmetry $$A_J$$ is investigated. It is interesting to find that dijets with larger $$A_J$$ have larger length-averaged $$\hat{q}$$ values. Our study suggests that dijets with different $$A_J$$ values can provide versatile tools for studying jet quenching and extracting jet Transport parameters.

  • extracting jet Transport parameter hat q from a multiphase Transport Model
    arXiv: High Energy Physics - Phenomenology, 2019
    Co-Authors: Fengchu Zhou, Y. G.
    Abstract:

    Within a multi-phase Transport Model with string melting scenario, jet Transport parameter $\hat{q}$ is calculated in Au+Au collisions at $\sqrt{s_{NN} } $= 200 GeV and Pb+Pb collisions at $\sqrt{s_{NN} } $= 2.76 TeV. The $\hat{q}$ increases with the increasing of jet energy for both partonic phase and hadronic phase. The energy and path length dependences of $\hat{q}$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet Transport parameter $\hat{q}$ and dijet transverse momentum asymmetry $A_{J}$ is mainly investigated, which discloses that a larger $\hat{q}$ corresponds to a larger $A_{J}$. It supports a consistent jet energy loss picture from the two viewpoints of single jet and dijet. It is proposed to measure dijet asymmetry distributions with different jet Transport parameter ranges as a new potential method to study jet quenching physics in high energy heavy-ion collisions.

  • Initial partonic eccentricity fluctuations in a multiphase Transport Model
    Physical Review C, 2016
    Co-Authors: Y. G.
    Abstract:

    Initial partonic eccentricities in Au+Au collisions at center-of-mass energy $\sqrt{s_{NN}}$ = 200 GeV are investigated using a multi-phase Transport Model with string melting scenario. The initial eccentricities in different order of harmonics are studied using participant and cumulant definitions. Eccentricity in terms of second-, fourth- and sixth order cumulants as a function of number of participant nucleons are compared systematically with the traditional participant definition. The ratio of the cumulant eccentricities $\varepsilon\left\{4\right\}/\varepsilon\left\{2\right\}$ and $\varepsilon\left\{6\right\}/\varepsilon\left\{4\right\}$ are studied in comparison with the ratio of the corresponding flow harmonics. The conversion coefficients ($v_n/\varepsilon_n$) are explored up to fourth order harmonic based on cumulant method. Furthermore, studies on transverse momentum ($p_T$) and pseudo-rapidity ($\eta$) dependencies of eccentricities and their fluctuations are presented. As in ideal hydrodynamics initial eccentricities are expected to be closely related to the final flow harmonics in relativistic heavy-ion collisions, studies of the fluctuating initial condition in the AMPT Model will shed light on the tomography properties of the initial source geometry.Comment: 13 pages, 8 figures; accepted by Phys. Rev.

  • initial partonic eccentricity fluctuations in a multiphase Transport Model
    Physical Review C, 2016
    Co-Authors: Y. G.
    Abstract:

    Initial partonic eccentricities in $\text{Au}+\text{Au}$ collisions at center-of-mass energy $\sqrt{{s}_{NN}}=200$ GeV are investigated by using a multiphase Transport Model with a string-melting scenario. The initial eccentricities in different order of harmonics are studied by using participant and cumulant definitions. Eccentricity in terms of second-, fourth- and sixth-order cumulants as a function of number of participant nucleons are compared systematically with the traditional participant definition. The ratio of the cumulant eccentricities $\ensuremath{\varepsilon}{4}/\ensuremath{\varepsilon}{2}$ and $\ensuremath{\varepsilon}{6}/\ensuremath{\varepsilon}{4}$ are studied in comparison with the ratio of the corresponding flow harmonics. The conversion coefficients (${v}_{n}/{\ensuremath{\varepsilon}}_{n}$) are explored up to fourth-order harmonics based on the cumulant method. Furthermore, studies on transverse momentum (${p}_{T}$) and pseudorapidity ($\ensuremath{\eta}$) dependencies of eccentricities and their fluctuations are presented. As in ideal hydrodynamics, initial eccentricities are expected to be closely related to the final flow harmonics in relativistic heavy-ion collisions, studies of the fluctuating initial condition in the AMPT Model will shed light on the tomography properties of the initial source geometry.

  • $\phi$-meson production at forward/backward rapidity in high-energy nuclear collisions from a multiphase Transport Model
    Physical Review C, 2016
    Co-Authors: J. H. Chen, Y. G., S. Q. Zhang, Chao Zhong
    Abstract:

    Within the framework of a multiphase Transport Model (AMPT), the $\phi$-meson production is studied in d+Au collisions at \srt = {200} GeV in the forward (d-going, $1.2

Qun Wang - One of the best experts on this subject based on the ideXlab platform.

  • global lambda polarization in heavy ion collisions from a Transport Model
    Physical Review C, 2017
    Co-Authors: Hui Li, Xiaoliang Xia, Longgang Pang, Qun Wang
    Abstract:

    The polarizations of $\Lambda$ and $\bar{\Lambda}$ hyperons are important quantities in extracting the fluid vorticity of the strongly coupled quark gluon plasma and the magnitude of the magnetic field created in off-central heavy-ion collisions, through the spin-vorticity and spin-magnetic coupling. We computed the energy dependence of the global $\Lambda$ polarization in off-central Au+Au collisions in the energy range $\sqrt{s_{NN}}=7.7-200$ GeV using a multiphase Transport Model. The observed polarizations with two different impact parameters agree quantitatively with recent STAR measurements. The energy dependence of the global $\Lambda$ polarization is decomposed as energy dependence of the $\Lambda$ distribution at hadronization and the space-time distribution of the fluid-vorticity field. The visualization of both the $\Lambda$ distribution and the fluid-vorticity field show a smaller tilt at higher collisional energies, which indicates that the smaller global polarization at higher collisional energies is caused by a smaller angular momentum deposition at midrapidity.

  • global λ polarization in heavy ion collisions from a Transport Model
    Physical Review C, 2017
    Co-Authors: Longgang Pang, Qun Wang, Xiaoliang Xia
    Abstract:

    Off-central relativistic heavy ion collisions impart very large orbital angular momenta onto the quark-gluon plasma, creating a strong vortex in the initial hot fluid and appearing eventually, via spin-vorticity coupling, as particle polarization. From the vorticity field given by a multi-phase Transport Model the authors compute the global polarization of $\mathrm{\ensuremath{\Lambda}}$ baryons which is in agreement with experimental data. This suggests that the spin of a hadron could provide information on quark-gluon plasma flow.

Fengchu Zhou - One of the best experts on this subject based on the ideXlab platform.

  • Extracting jet Transport parameter $\hat{q}$ from a multiphase Transport Model
    The European Physical Journal A, 2020
    Co-Authors: Fengchu Zhou
    Abstract:

    Within a multi-phase Transport Model with string melting scenario, jet Transport parameter $\hat{q}$ is calculated in Au+Au collisions at $\sqrt{s_{NN} } $= 200 GeV and Pb+Pb collisions at $\sqrt{s_{NN} } $= 2.76 TeV. The $\hat{q}$ increases with the increasing of jet energy for both partonic phase and hadronic phase. The energy and path length dependences of $\hat{q}$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet Transport parameter $\hat{q}$ and dijet transverse momentum asymmetry $A_{J}$ is mainly investigated, which discloses that a larger $\hat{q}$ corresponds to a larger $A_{J}$. It supports a consistent jet energy loss picture from the two viewpoints of single jet and dijet. It is proposed to measure dijet asymmetry distributions with different jet Transport parameter ranges as a new potential method to study jet quenching physics in high energy heavy-ion collisions.

  • extracting jet Transport parameter hat q from a multiphase Transport Model
    European Physical Journal A, 2020
    Co-Authors: Fengchu Zhou, Y. G.
    Abstract:

    Within a multiphase Transport Model with a string-melting scenario, the jet Transport parameter $$\hat{q}$$ is extracted in Au+Au collisions at $$\sqrt{s_{NN} } $$= 200 GeV and Pb+Pb collisions at $$\sqrt{s_{NN} } $$= 2.76 TeV. The jet Transport parameter $$\hat{q}$$ is a key parameter in jet-quenching phenomena, which depends not only on the temperature of the QCD medium but also on jet energy. We observe that $$\hat{q}$$ increases with increasing of the jet energy for both the partonic phase and the hadronic phase. The energy and path length dependences of $$\hat{q}$$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet Transport parameter $$\hat{q}$$ and dijet transverse momentum asymmetry $$A_J$$ is investigated. It is interesting to find that dijets with larger $$A_J$$ have larger length-averaged $$\hat{q}$$ values. Our study suggests that dijets with different $$A_J$$ values can provide versatile tools for studying jet quenching and extracting jet Transport parameters.

  • extracting jet Transport parameter hat q from a multiphase Transport Model
    arXiv: High Energy Physics - Phenomenology, 2019
    Co-Authors: Fengchu Zhou, Y. G.
    Abstract:

    Within a multi-phase Transport Model with string melting scenario, jet Transport parameter $\hat{q}$ is calculated in Au+Au collisions at $\sqrt{s_{NN} } $= 200 GeV and Pb+Pb collisions at $\sqrt{s_{NN} } $= 2.76 TeV. The $\hat{q}$ increases with the increasing of jet energy for both partonic phase and hadronic phase. The energy and path length dependences of $\hat{q}$ in full heavy-ion evolution are consistent with the expectations of jet quenching. The correlation between jet Transport parameter $\hat{q}$ and dijet transverse momentum asymmetry $A_{J}$ is mainly investigated, which discloses that a larger $\hat{q}$ corresponds to a larger $A_{J}$. It supports a consistent jet energy loss picture from the two viewpoints of single jet and dijet. It is proposed to measure dijet asymmetry distributions with different jet Transport parameter ranges as a new potential method to study jet quenching physics in high energy heavy-ion collisions.

Bin Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Multiphase Transport Model for heavy ion collisions at RHIC
    Nuclear Physics A, 2002
    Co-Authors: Ziwei Lin, Subrata Pal, Bin Zhang
    Abstract:

    Using a multiphase Transport Model (AMPT) with both partonic and hadronic interactions, we study the multiplicity and transverse momentum distributions of charged particles such as pions, kaons and protons in central Au+Au collisions at RHIC energies. Effects due to nuclear shadowing and jet quenching on these observables are also studied. We further show preliminary results on the production of multistrange baryons from the strangeness-exchange reactions during the hadronic stage of heavy ion collisions.Comment: 4 pages, 4 figures, espcrc1.sty included, presented at 15th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2001), Long Island, New York, January 200

  • Multiphase Transport Model for relativistic nuclear collisions
    Physical Review C, 2000
    Co-Authors: Bin Zhang, Ziwei Lin
    Abstract:

    To study heavy ion collisions at energies available from the Relativistic Heavy Ion Collider ~RHIC! ,w e have developed a multiphase Transport Model that includes both initial partonic and final hadronic interactions. Specifically, the Zhang’s parton cascade ~ZPC! Model, which uses as input the parton distribution from the heavy ion jet interaction generator ~HIJING! Model, is extended to include the quark-gluon‐to‐hadronicmatter transition and also final-state hadronic interactions based on a relativistic Transport ~ART! Model. Predictions of the Model for central Au on Au collisions at RHIC are reported. PACS number~s!: 25.75.2q, 24.10.Lx, 24.10.Jv The beginning of experiments at the Relativistic Heavy Ion Collider ~RHIC! this year will start an exciting new era in nuclear and particle physics. The estimated high energy density in central heavy ion collisions at RHIC is expected to lead to the formation of a large region of deconfined matter of quarks and gluons, the quark gluon plasma ~QGP!. This would give us the opportunity to study the properties of the QGP and its transition to hadronic matter, which would then shed light on the underlying fundamental theory of strong interactions, quantum chromodynamics ~QCD!. Because of the complexity of heavy ion collision dynamics, Monte Carlo event generators are needed to relate the experimental observations to the underlying theory. This has already been shown to be the case in heavy ion collisions at existing accelerators such as the SIS, AGS, and SPS @1‐6#. As minijet production is expected to play an important role at RHIC energies @7#, Models for partonic Transport have been studied @8,9#. Furthermore, Transport Models that include both partonic and hadronic degrees of freedom are being developed @10,11#. We have recently also developed such a multiphase Transport ~AMPT! Model. It starts from initial conditions that are motivated by perturbative QCD and incorporates the subsequent partonic and hadronic spacetime evolution. In particular, we have used the heavy ion jet interaction generator ~HIJING! Model @7# to generate the initial phase space distribution of partons and the Zhang’s parton cascade ~ZPC! Model @9# to follow their rescatterings. A modified HIJING fragmentation scheme is then introduced for treating the hadronization of the partonic matter. The evolution of the resulting hadron system is treated in the framework of a relativistic Transport ~ART! Model @2#. In this paper, we shall describe this new multiphase Transport Model and show its predictions for central Au-on-Au collisions at RHIC.

C. C. Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Revisiting directed flow in relativistic heavy-ion collisions from a multiphase Transport Model
    The European Physical Journal A, 2017
    Co-Authors: Chong-qiang Guo, C. C. Zhang
    Abstract:

    We have revisited several interesting questions on how the rapidity-odd directed flow is developed in relativistic 197Au+197Au collisions at \( \sqrt{s_{NN}} = 200\) and 39 GeV based on a multiphase Transport Model. As the partonic phase evolves with time, the slope of the parton directed flow at midrapidity region changes from negative to positive as a result of the later dynamics at 200 GeV, while it remains negative at 39 GeV due to the shorter life time of the partonic phase. The directed flow splitting for various quark species due to their different initial eccentricities is observed at 39 GeV, while the splitting is very small at 200GeV. From a dynamical coalescence algorithm with Wigner functions, we found that the directed flow of hadrons is a result of competition between the coalescence in momentum and coordinate space as well as further modifications by the hadronic rescatterings.

  • Directed flow in relativistic heavy-ion collisions from a multiphase Transport Model
    arXiv: Nuclear Theory, 2017
    Co-Authors: Chong-qiang Guo, C. C. Zhang
    Abstract:

    We have studied the directed flow in $^{197}$Au+$^{197}$Au collisions at $\sqrt{s_{NN}}$ = 200 and 39 GeV within a multiphase Transport Model. As the partonic phase evolves with time, the slope of the parton directed flow at mid-rapidity region changes from negative to positive as a result of the later dynamics at 200 GeV, while it remains negative at 39 GeV due to the shorter life time of the partonic phase. The directed flow splitting for various quark species due to their different initial eccentricities is observed at 39 GeV, while the splitting is very small at 200 GeV. Effects of the hadronization and the hadronic rescatterings on the directed flow are further discussed. Our study serves as a baseline on the understanding of the directed flow in the absence of the mean-field potentials and other exotic mechanisms.