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Sheng-Qin Feng

Publications and source records attributed to Sheng-Qin Feng.

32 records · Page 2Linked to original sources
arXiv2018

Chiral magnetic currents with QGP medium response in heavy ion collisions at RHIC and LHC energies

We calculate the electromagnetic current with a more realistic approach in the RHIC and LHC energy regions in the article. We take the partons formation time as the initial time of the magnetic field response of QGP medium. The maximum electromagnetic current and the time-integrated current are two important characteristics of the chiral magnetic effect (CME), which can characterize the intensity and duration of fluctuations of CME. We consider the finite frequency response of CME to a time-varying magnetic field, find a significant impact from QGP medium feedback, and estimate the generated electromagnetic current as a function of time, beam energy and impact parameter.

hep-ph↗
arXiv2018

Moving heavy quarkonium entropy, effective string tension, and the QCD phase diagram

The entropy and effective string tension of the moving heavy quark-antiquark pair in the strongly coupled plasmas are calculated by using a deformed an anti-de Sitter/Reissner-Nordstr$\ddot{o}$m black hole metric. A sharp peak of the heavy-quarkonium entropy around the deconfinement transition can be realized in our model, which is consistent with the lattice QCD result. The effective string tension of the heavy quark-antiquark pair is related to the deconfinement phase transition. Thus, we investigate the deconfinement phase transition by analyzing the characteristics of the effective string tension with different temperatures, chemical potentials, and rapidities. It is found that the results of phase diagram calculated through effective string tension are in agreement with results calculated through a Polyakov loop. We argue that a moving system will reach the phase transition point at a lower temperature and chemical potential than a stationary system. It means that the lifetime of the moving QGP becomes longer than the static one.

hep-ph↗
arXiv2018

Estimation of the chiral magnetic effect considering the magnetic field response of the QGP medium

The magnetic field plays a major role in the searching of the chiral magnetic effect in relativistic heavy-ion collisions. If the lifetime of the magnetic field is too short, as expected by simulations of the field in the vacuum, the chiral magnetic effect will be largely suppressed. However, the lifetime of the magnetic field will become longer when the QGP medium response is considered. We give an estimate of the effect, especially considering the magnetic field response of the QGP medium, and compare it with the experimental results of background-subtracted correlator $H$ at RHIC and LHC energies. The results show that our method explains better for the experimental results at the top RHIC energy than that of the LHC energy.

nucl-th↗
arXiv2016

Chiral electric field in relativistic heavy-ion collisions at energies available at the BNL Relativistic Heavy Ion Collider and at the CERN Large Hadron Collider

It was proposed that the electric fields may lead to chiral separation in QGP, which is called the chiral electric separation effect. The strong electromagnetic field and the QCD vacuum can both completely be produced in the off-central nuclear-nuclear collision. We used the Wood-Saxon nucleon distribution to calculate the electric field distributions of the off-central collisions. The chiral electro field spatial distribution at Relativistic Heavy-Ion Collider (RHIC) and Large Hadron Collider (LHC) energy regions are systematically studied in this paper. Compared with magnetic field spatial distribution, electric field shows some different features in relativistic heavy-ion collisions. The dependence of the electric field produced by the thermal quark in the central position with different impact parameters on the proper time with different collision energies in the RHIC and LHC energy region are studied in this paper.

hep-ph↗
arXiv2015

The spatial distributions of chiral magnetic field in the RHIC and LHC energy regions

Relativistic heavy-ion collisions can produce extremely strong magnetic field in the collision regions. The spatial variation features of the magnetic fields are analyzed in detail for non-central Pb - Pb collisions at LHC $\sqrt{s_{NN}}$= 900, 2760 and 7000 GeV and Au-Au collisions at RHIC $\sqrt{s_{NN}}$ = 62.4, 130 and 200 GeV. The dependencies of magnetic field on proper time, collision energies and impact parameters are investigated in this paper. It is shown that a enormous with highly inhomogeneous spatial distribution magnetic field can indeed be created in off-central relativistic heavy-ion collisions in RHIC and LHC energy regions. The enormous magnetic field is quite large, especially just after the collision, and then decreases rapidly with time. We are surprised to find that the magnetic effect decreases with increasing energy from RHIC to LHC energy region. It is found that the magnitude of magnetic field in the LHC energy region is far less than that of magnetic field in the RHIC energy region.

hep-ph↗
arXiv2014

Gluon saturation and pseudo-rapidity distributions of charged hadrons at RHIC energy regions

We modified the gluon saturation model by rescaling the momentum fraction according to saturation momentum and introduced the Cooper-Frye hydrodynamic evolution to systematically study the pseudo-rapidity distributions of final charged hadrons at different energies and different centralities for Au-Au collisions in relativistic heavy-ion collisions at BNL Relativistic Heavy Ion Collider (RHIC). The features of both gluon saturation and hydrodynamic evolution at different energies and different centralities for Au-Au collisions are investigated in this paper.

hep-ph↗
arXiv2014

Thermalization component model of multiplicity distributions of charged hadrons at BNL($E^{lab}_{NN}=2-11.6GeV/c$), the CERN($E^{lab}_{NN}=20-200GeV/c$), and the BNL ($\sqrt{s_{NN}}=19.6-200 GeV$)

We find that collective flow model which can successfully analyze charged particle distributions at AGS and lower SPS (less than 20Gev/n). but fails to analyze that of at RHIC. The tails of distribution of charged particle at RHIC has a jump from the collective flow model calculation as the energy increases. Thermalization Component Model is presented based on collective flow to study the multiplicity distributions at RHIC in this paper. It is realized that the region of phase space of collective flow can reflect that of thermalization region. By comparing the contributions of particle productions from thermalization region at different energies and different centralities, we can deepen our study on the feature of collective movement at RHIC. Keywords: Thermalization, Thermalization component model

nucl-th↗
arXiv2014

Strange particles production in relativistic nucleus-nucleus collisions at RHIC and LHC energy regions

PACIAE, a parton and hadron cascade model, is utilized to systematically investigate strange particle production and strangeness enhancement in Au+Au collision and in Pb+Pb collision with the 200GeV at RHIC and 2.76TeV at LHC, respectively. The experimental results at different centrality, which come from the STAR collaboration and the ALICE collaboration, are well described by the PACIAE model. This may represent the importance of the parton and hadron rescatterings, as well as the reduction mechanism of strange quark suppression, added in the PACIAE model.

hep-ph↗
arXiv2013

Effect of the Wood-Saxon nuclear distribution on the chiral magnetic field in Relativistic Heavy-ion Collisions

The formation of the QCD vacuum with nonzero winding number $Q_w$ during relativistic heavy-ion collisions breaks the parity and charge-parity symmetry. A new kind of field configuration can separate charge in the presence of a background magnetic field-the "chiral magnetic effect". The strong magnetic field and the QCD vacuum can both completely be produced in the noncentral nuclear-nuclear collision. Basing on the theory of Kharzeev,Mclerran and Warringa, we use the Wood-Saxon nucleon distribution to replace that of the uniform distribution to improve the magnetic field calculation method of the noncentral collision. The chiral magnetic field distribution at LHC(Large Hadron Collider) energy regions are predicted. We also consider the contributions to the magnetic field of the total charge given by the produced quarks.

hep-ph↗
arXiv2012

Gluon saturation and baryon stopping in the SPS, RHIC and LHC energy regions

A new geometrical scaling method with gluon saturation rapidity limit is proposed to study the gluon saturation feature of the central rapidity region of relativistic nuclear collisions. The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. We take advantage of the gluon saturation model with geometric scaling of the rapidity limit to investigate the net baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions. Predictions for net-baryon rapidity distributions, the mean rapidity loss and gluon saturation feature in central Pb + Pb collisions at LHC are made in this paper.

hep-ph↗
arXiv2012

Baryon productions and collective flow of relativistic heavy-ion collisions in the AGS, SPS, RHIC and LHC energy regions($\sqrt{s_{NN}}\leq5$GeV to 5.5 TeV)

The features of net baryon productions and collective flow in relativistic heavy-ion collisions at energies reached at the CERN Large Hadron Collider (LHC), BNL Relativistic Heavy Ion Collider (RHIC), CERN Super Proton Synchrotron (SPS) and BNL Alternating Gradient Synchrotron (AGS) with the model of Non-Uniform Flow Model(NUFM) are systematically studied in this paper. Especially we predict the feature of net baryon productions and collective flow at LHC $\sqrt{s_{NN}}$=5500 GeV basing on the detailed study of that at RHIC $\sqrt{s_{NN}}$=62.4 and 200GeV. The dependencies of the features of baryon stopping and collective flow on the collision energies and centralities are investigated.

hep-ph↗
arXiv2012

Strange quark suppression and strange hadron production in pp collisions at RHIC and LHC

The parton and hadron cascade model PACIAE based on PYTHIA was utilized to systematically investigate the strange particle production in pp collisions at the RHIC and LHC energies. Taking the mechanism of reduction of the strange quark suppression into account the STAR and ALICE data of strange particle production in pp collisions are well reproduced. It turned out that the K/π ratio as a function of reaction energy in pp collisions shows slightly increasing from sqrt(s)=0.2 to 0.9 TeV and then turning to saturation.

hep-ph↗
arXiv2011

PACIAE 2.0: An updated parton and hadron cascade model (program) for the relativistic nuclear collisions

We have updated the parton and hadron cascade model PACIAE for the relativistic nuclear collisions, from based on JETSET 6.4 and PYTHIA 5.7 to based on PYTHIA 6.4, and renamed as PACIAE 2.0. The main physics concerning the stages of the parton initiation, parton rescattering, hadronization, and hadron rescattering were discussed. The structures of the programs were briefly explained. In addition, some calculated examples were compared with the experimental data. It turns out that this model (program) works well.

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