arXiv subjects

Bao-Chun Li

Publications and source records attributed to Bao-Chun Li.

16 recordsLinked to original sources

arXiv2019

Investigation of particle distributions in Xe-Xe collision at 5.44 TeV with Tsallis statistics

The distribution characteristic of final-state particles is one of significant parts in high energy nuclear collisions. The transverse momentum distribution of charged particles carries essential evolution information about the collision system. Tsallis statistics is used to investigate the transverse momentum distribution of charged particles produced in Xe-Xe collisions at 5.44 TeV. On the basis, we reproduce the nuclear modification factor of the charged particles. The calculated results agree approximately with the experimental data measured by the ALICE Collaboration.

hep-ph↗

arXiv2019

Multisource thermal model to the transverse momentum spectra in pp collisions at RHIC and LHC energies

In this paper, an improved multi-source thermal model is used to analyze the transverse momentum spectra in $pp$ collisions at high energies ranging from $\sqrt{\mathrm{\it s_{NN}}}$ = 62.4 GeV to 7 TeV. We give a detailed comparison between the theoretical results and experimental data at RHIC and LHC energies. It is shown that the excitation factors of emission sources depend linearly on ln$\sqrt{\mathrm{\it s_{NN}}}$ in the framework. Based on the variation regularity of the source-excitation factors, transverse momentum spectra are predicted in $pp$ collisions at higher energies, potential future $pp$ colliders operating at $\sqrt{\mathrm{\it s_{NN}}}$ = 33 and 100 TeV.

hep-ph↗

arXiv2019

Kinetic freeze-out temperature and transverse flow velocity in Au-Au collisions at RHIC-BES energies

Based on the data-driven analysis, the mid-rapidity transverse momentum spectra of charged hadrons produced in central and peripheral gold-gold (Au-Au) collisions from the Beam Energy Scan (BES) program at the relativistic Heavy Ion Collider (RHIC) are fitted by the blast-wave model with Boltzmann-Gibbs statistics. The model result are in agreement with the experimental data measured by the STAR Collaboration at the RHIC-BES energies. We observe that the kinetic freeze-out temperature, transverse flow velocity, mean transverse momentum, and initial temperature increase with the collision energy and with the event centrality.

hep-ph↗

arXiv2019

Transverse momentum and pseudorapidity dependence of particle production in Xe-Xe collision at 5.44 TeV

Through the collision-system configuration, the Tsallis statistics is combined with a multisource thermal model. The improved model is used to investigate the transverse momentum and pseudorapidity of particles produced in Xe-Xe collisions at 5.44 TeV. We discuss detailedly the thermodynamic properties, which are taken from the transverse momentum distributions of pion, kaon and proton for different centralities. The pseudorapidity spectra of charged particles for different centralities are described consistently in the model. And, the model result can estimate intuitively the longitudinal configuration of the collision system. PACS numbers: 13.85.-t, 14.40.-n, 12.40.Ee

hep-ph↗

arXiv2019

Rapidity dependent transverse momentum spectra of heavy quarkonia produced in small collision systems at the LHC

The rapidity dependent transverse momentum spectra of heavy quarkonia (J/psi and Upsilon mesons) produced in small collision systems such as proton-proton (pp) and proton-lead (p-Pb) collisions at center-of-mass energy (per nucleon pair) 5-13 TeV are described by a two-component statistical model which is based on the Tsallis statistics and inverse power-law. The experimental data measured by the LHCb Collaboration at the Large Hadron Collider (LHC) are well fitted by the model results. The related parameters are obtained and the dependences of parameters on rapidity are analyzed.

hep-ph↗

arXiv2018

Examining the model dependence of the determination of kinetic freeze-out temperature and transverse flow velocity in small collision system

The transverse momentum distributions of the identified particles produced in small collision systems at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) have been analyzed by four models. The first two models utilize the blast-wave model with different statistics. The last two models employ certain linear correspondences based on different distributions. The four models describe the experimental data measured by the Pioneering High Energy Nuclear Interaction eXperiment (PHENIX), Solenoidal Tracker at RHIC (STAR), and A Large Ion Collider Experiment (ALICE) cCollaborations equally well. It is found that both the kinetic freeze-out temperature and transverse flow velocity in the central collisions are comparable with those in the peripheral collisions. With the increase of collision energy from that of the RHIC to that of the LHC, the considered quantities typically do not decrease. Comparing with the central collisions, the proton-proton collisions are closer to the peripheral collisions.

nucl-th↗

arXiv2018

Angular dependence of eta photoproduction in photon-induced reaction

Photoproduction of eta mesons from nucleons can provide valuable information about the excitation spectrum of the nucleons. The angular dependence of photoproduction in the photon-induced reaction is investigated in the multi-source thermal model. The results are compared with experimental data from the decay mode. They are in good agreement with the experimental data. It is shown that the movement factor increases linearly with the photon beam energies. And, the deformation and translation of emission sources are visually given in the formalism.

nucl-th↗

arXiv2018

Kinetic freeze-out temperatures in central and peripheral collisions: Which one is larger?

The kinetic freeze-out temperatures, $T_0$, in nucleus-nucleus collisions at the Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies are extracted by four methods: i) the Blast-Wave model with Boltzmann-Gibbs statistics (the BGBW model), ii) the Blast-Wave model with Tsallis statistics (the TBW model), iii) the Tsallis distribution with flow effect (the improved Tsallis distribution), and iv) the intercept in $T=T_0+am_0$ (the alternative method), where $m_0$ denotes the rest mass and $T$ denotes the effective temperature which can be obtained by different distribution functions. It is found that the relative sizes of $T_0$ in central and peripheral collisions obtained by the conventional BGBW model which uses a zero or nearly zero transverse flow velocity, $β_T$, are contradictory in tendency with other methods. With a re-examination for $β_T$ in the first method in which $β_T$ is taken to be $\sim(0.40\pm0.07)c$, a recalculation presents a consistent result with others. Finally, our results show that the kinetic freeze-out temperature in central collisions is larger than that in peripheral collisions.

nucl-th↗

arXiv2017

On J/psi and transverse momentum distributions in high energy collisions

The transverse momentum distributions of final-state particles are very important for high-energy collision physics. In this work, we investigate and meson distributions in the framework of a particle-production source, where Tsallis statistics are consistently integrated. The results are in good agreement with the experimental data of proton-proton ( ) and proton-lead ( -Pb) collisions at LHC energies. The temperature of the emission source and the nonequilibrium degree of the collision system are extracted.

nucl-th↗

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↗

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.

nucl-th↗

arXiv2011

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

nucl-th↗

arXiv2009

Thermodynamic properties and bulk viscosity near phase transition in the Z(2) and O(4) models

We investigate the thermodynamic properties including equation of state, the trace anomaly, the sound velocity and the specific heat, as well as transport properties like bulk viscosity in the Z(2) and O(4) models in the Hartree approximation of Cornwall-Jackiw-Tomboulis (CJT) formalism. We study these properties in different cases, e.g. first order phase transition, second order phase transition, crossover and the case without phase transition, and discuss the correlation between the bulk viscosity and the thermodynamic properties of the system. We find that the bulk viscosity over entropy density ratio exhibits an upward cusp at the second order phase transition, and a sharp peak at the 1st order phase transition. However, this peak becomes smooth or disappears in the case of crossover. This indicates that at RHIC, where there is no real phase transition and the system experiences a crossover, the bulk viscosity over entropy density might be small, and it will not affect too much on hadronization. We also suggest that the bulk viscosity over entropy density ratio is a better quantity than the shear viscosity over entropy density ratio to locate the critical endpoint.

hep-ph↗

arXiv2008

Strongly coupled matter near phase transition

In the Hartree approximation of Cornwall-Jackiw-Tomboulis (CJT) formalism of the real scalar field theory, we show that for the strongly coupled scalar system near phase transition, the shear viscosity over entropy density is small, however, the bulk viscosity over entropy density is large. The large bulk viscosity is related to the highly nonconformal equation of state. It is found that the square of the sound velocity near phase transition is much smaller than the conformal value 1/3, and the trace anomaly at phase transition deviates far away from 0. These results agree well with the lattice results of the complex QCD system near phase transition.

hep-ph↗

arXiv2008

Non-conformality and non-perfectness of fluid near phase transition

We investigate the thermodynamic and transport properties of the real scalar field theory at weak as well as strong couplings in the Hartree approximation of Cornwall-Jackiw-Tomboulis (CJT) formalism. To our surprise, we find that near phase transition, all the thermodynamic and transport properties of the simplest real scalar model at certain strong coupling agree well with the lattice results of the complex QCD system. We also demonstrate that the system near phase transition is non-conformal, and behaves as a non-perfect fluid.

hep-ph↗