arXiv subjects

Fu-Hu Liu

Publications and source records attributed to Fu-Hu Liu.

86 records · Page 5Linked to original sources

arXiv2016

Kinetic freeze-out temperature and flow velocity extracted from transverse momentum spectra of final-state light flavor particles produced in collisions at RHIC and LHC

The transverse momentum spectra of final-state light flavor particles produced in proton-proton (p-p), copper-copper (Cu-Cu), gold-gold (Au-Au), lead-lead (Pb-Pb), and proton-lead (p-Pb) collisions for different centralities at relativistic heavy ion collider (RHIC) and large hadron collider (LHC) energies are studied in the framework of a multisource thermal model. The experimental data measured by the STAR, CMS, and ALICE Collaborations are consistent with the results calculated by the multi-component Erlang distribution and Tsallis Statistics. The effective temperature and real temperature (kinetic freeze-out temperature) of interacting system at the stage of kinetic freeze-out, the mean transverse flow velocity and mean flow velocity of particles, and the relationships between them are extracted. The dependences of effective temperature and mean (transverse) momentum on rest mass, moving mass, centrality, and center-of-mass energy, and the dependences of kinetic freeze-out temperature and mean (transverse) flow velocity on centrality, center-of-mass energy, and system size are obtained.

hep-ph↗

arXiv2016

Comparing Erlang distribution and Schwinger mechanism on transverse momentum spectra in high energy collisions

We study the transverse momentum spectra of J/psi and Upsilon mesons by using two methods: the two-component Erlang distribution and the two-component Schwinger mechanism. The results obtained by the two methods are compared and found to be in agreement with the experimental data of proton-proton (pp), proton-lead (p-Pb), and lead-lead (Pb-Pb) collisions measured by the LHCb and ALICE Collaborations at the large hadron collider (LHC). The related parameters such as the mean transverse momentum contributed by each parton in the first (second) component in the two-component Erlang distribution and the string tension between two partons in the first (second) component in the two-component Schwinger mechanism are extracted.

hep-ph↗

arXiv2015

On Distributions of Emission Sources and Speed of Sound in Proton-proton (Proton-antiproton) Collisions

The revised (three-source) Landau hydrodynamic model is used in this paper to study the (pseudo)rapidity distributions of charged particles produced in proton-proton and proton-antiproton collisions at high energies. The central source is assumed to contribute with a Gaussian function which covers the rapidity distribution region as wide as possible. The target and projectile sources are assumed to emit isotropically particles in their respective rest frames. The model calculations obtained with a Monte Carlo method are fitted to the experimental data over an energy range from 0.2 to 13 TeV. The values of the squared speed-of-sound parameter in different collisions are then extracted from the width of the rapidity distributions.

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arXiv2015

Transverse momentum and pseudorapidity distributions of final-state particles and spatial structure pictures of interacting system in p-Pb collisions at \sqrt{s_{NN}}=5.02 TeV

The transverse momentum and pseudorapidity distributions of final-state particles produced in proton-lead (p-Pb) collisions at center-of-mass energy per nucleon pair \sqrt{s_{NN}}=5.02 TeV are studied in the framework of a multisource thermal model. Experimental results measured by the ALICE and CMS Collaborations are described by the Tsallis transverse momentum distribution and the two-cylinder pseudorapidity distribution. Based on the parameter values extracted from the transverse momentum and pseudorapidity distributions, some other quantities are extracted. Then, the structure pictures of interacting system at the stage of kinetic freeze-out in some spaces are obtained.

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arXiv2015

On Extraction of Chemical Potentials of Quarks from Particle Transverse Momentum Spectra in High Energy Collisions

We present two methods to extract the chemical potentials of quarks in high energy collisions. The first method is based on the ratios of negatively/positively charged particles, and the temperatures extracted from the transverse momentum spectra of related hadrons are needed. The second method is based on the chemical potentials of some particles, and we also need the transverse momentum spectra of related hadrons. To extract the quark chemical potentials, we would like to propose experimental collaborations to measure simultaneously not only the transverse momentum spectra of anti-p, p, K^-, K^+, pion^-, and pion^+, but also those of D^-, D^+, B^-, and B^+ (even those of Delta^++, Delta^-, and Omega^-) in high energy nuclear collisions

hep-ph↗

arXiv2015

On pseudorapidity distribution and speed of sound in high energy heavy ion collisions based on a new revised Landau hydrodynamic model

We propose a new revised Landau hydrodynamic model to study systematically the pseudorapidity distributions of charged particles produced in heavy ion collisions over an energy range from a few GeV to a few TeV per nucleon pair. The interacting system is divided into three sources namely the central, target, and projectile sources respectively. The large central source is described by the Landau hydrodynamic model and further revised by the contributions of the small target/projectile sources. In the calculation, to avoid the errors caused by an unapt conversion or non-division, the rapidity and pseudorapidity distributions are obtained respectively. The modeling results are in agreement with the available experimental data at relativistic heavy ion collider (RHIC), large hadron collider (LHC), and other energies for different centralities. The value of square speed of sound parameter in different collisions has been extracted by us from the widths of rapidity distributions. Our results show that, in heavy ion collisions at RHIC and LHC energies, the central source undergoes through a phase transition from hadronic gas to quark-gluon plasma (QGP) liquid phase; meanwhile, the target/projectile sources remain in the state of hadronic gas. The present work confirms that the QGP is of liquid type rather than that of a gas. The whole region of participants undergoes through a mixed phase consisting of a large quantity of (>90%) QGP liquid and a small quantity of (<10%) hadronic gas.

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arXiv2015

A study of transverse momentum distributions of jets produced in p-p, p-\bar p, d-Au, Au-Au, and Pb-Pb collisions at high energies

The transverse momentum distributions of jets produced in p-p, p-\bar p, d-Au, Au-Au, and Pb-Pb collisions at high energies with different selected conditions are analyzed by using a multi-source thermal model. The multi-component (mostly two-component) Erlang distribution used in our description is in good agreement with the experimental data measured by the STAR, D0, CDF II, ALICE, ATLAS, and CMS Collaborations. Related parameters are extracted from the transverse momentum distributions and some information on different interacting systems are obtained. In the two-component Erlang distribution, the first component has usually two or more sources which are contributed by strong scattering interactions between two quarks or more quarks and gluons, while the second component has mostly two sources which are contributed by harder head-on scattering between two quarks.

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arXiv2015

On Productions of Net-baryons in Central Au-Au Collisions at RHIC Energies

The transverse momentum and rapidity distributions of net-baryons (baryons minus anti-baryons) produced in central gold-gold (Au-Au) collisions at 62.4 and 200 GeV are analyzed in the framework of a multisource thermal model. Each source in the model is described by the Tsallis statistics to extract the effective temperature and entropy index from the transverse momentum distribution. The two parameters are used as input to describe the rapidity distribution and to extract the rapidity shift and contribution ratio. Then, the four types of parameters are used to structure some scatter plots of the considered particles in some three-dimensional (3D) spaces at the stage of kinetic freeze-out, which are expected to show different characteristics for different particles and processes. The related methodology can be used in the analyzes of particle production and event holography, which are useful for us to better understand the interacting mechanisms.

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arXiv2014

Particle production in relativistic $pp$($\overline{p}$) and $AA$ collisions at RHIC and LHC energies with Tsallis statistics using the two-cylindrical multisource thermal model

An improved Tsallis statistics is implemented in a multisource thermal model to describe systematically pseudorapidity spectra of charged particles produced in relativistic nucleon-nucleon ($pp$ or $p\overline{p}$) collisions at various collision energies and in relativistic nucleus-nucleus ($AA$) collisions at different energies with different centralities. The results with Tsallis statistics using the two-cylindrical multisource thermal model are in good agreement with the experimental data measured at RHIC and LHC energies. It is found that the rapidity shifts of longitudinal sources increase linearly with collision energies and centralities in the framework. According to the laws, we also give a prediction of the pseudorapidity distributions in $pp$($\overline{p}$) collisions at higher energies.

hep-ph↗

arXiv2014

Formulation of transverse mass distributions in Au-Au collisions at 200 GeV/nucleon

The transverse mass spectra of light mesons produced in Au-Au collisions at 200 GeV/nucleon are analyzed in Tsallis statistics. In high energy collisions, it has been found that the spectra follow a generalized scaling law. We applied Tsallis statistics to the description of different particles using the scaling properties. The calculated results are in agreement with experimental data of PHENIX Collaboration. And, the temperature of emission sources is extracted consistently.

hep-ph↗

arXiv2013

Acoustic scaling of anisotropic flow in shape-engineered events: implications for extraction of the specific shear viscosity of the quark gluon plasma

It is shown that the acoustic scaling patterns of anisotropic flow for different event shapes at a fixed collision centrality (shape-engineered events), provide robust constraints for the event-by-event fluctuations in the initial-state density distribution from ultrarelativistic heavy ion collisions. The empirical scaling parameters also provide a dual-path method for extracting the specific shear viscosity $(η/s)_\mathrm{QGP}$ of the quark-gluon plasma (QGP) produced in these collisions. A calibration of these scaling parameters via detailed viscous hydrodynamical model calculations, gives $(η/s)_\mathrm{QGP}$ estimates for the plasma produced in collisions of Au+Au ($\sqrt{s_{NN}}= 0.2$ TeV) and Pb+Pb ($\sqrt{s_{NN}}= 2.76$ TeV). The estimates are insensitive to the initial-state geometry models considered.

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arXiv2011

Dependence of elliptic flow on transverse momentum in $\sqrt{\mathrm{\it s_{NN}}}=200$ GeV Au-Au and $\sqrt{\mathrm{\it s_{NN}=2.76$ TeV Pb-Pb collisions

We investigate the dependence of elliptic flows $v_2$ on transverse momentum $P_T$ for charged hadrons produced in nucleus-nucleus collisions at high energy by using a multi-source ideal gas model which includes the interaction contribution of the emission sources. Our calculated results are approximately in agreement with the experimental data over a wider $P_T$ range from the STAR and ALICE Collaborations. It is found that the expansion factor increases linearly with the impact parameter from most central (0-5%) to mid-peripheral (35-40%) collisions.

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arXiv2011

Dependence of elliptic flow on transverse momentum in 200 GeV Au-Au and 2.76 TeV Pb-Pb collisions

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arXiv2010

Transport model study of nuclear stopping in heavy ion collisions over an energy range from 0.09A GeV to 160A GeV

Nuclear stopping in the heavy ion collisions over a beam energy range from SIS, AGS up to SPS is studied in the framework of the modified UrQMD transport model, in which mean field potentials of both formed and "pre-formed" hadrons (from string fragmentation) and medium modified nucleon-nucleon elastic cross sections are considered. It is found that the nuclear stopping is influenced by both the stiffness of the equation of state and the medium modifications of nucleon-nucleon cross sections at SIS energies. At the high SPS energies, the two-bump structure is shown in the experimental rapidity distribution of free protons, which can be understood with the consideration of the "pre-formed" hadron potentials.

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