scholarly journals Rotation and spin dynamics in heavy-ion collisions

2018 ◽  
Vol 191 ◽  
pp. 05006
Author(s):  
G.Yu. Prokhorov ◽  
V.I. Zakharov ◽  
O.V. Teryaev
Keyword(s):  
Chemical Potential ◽  
Spin Dynamics ◽  
Heavy Ion ◽  
Axial Current ◽  
Two Dimensional ◽  
Zero Temperature ◽  
Mass Limit ◽  
Statistical Average ◽  
Plane Region ◽  
Ion Collisions

Statistical average of the axial current is evaluated on the basis of the covariantWigner function. In the zero-mass limit, the axial current is described by a smooth function only at temperatures higher than the Unruh temperature. At zero temperature, the axial current, as a function of the angular velocity and chemical potential, vanishes in a two-dimensional plane region.

scholarly journals Finite Temperature QCD Sum Rules: A Review

2017 ◽  
Vol 2017 ◽  
pp. 1-24 ◽  
Author(s):  
Alejandro Ayala ◽  
C. A. Dominguez ◽  
M. Loewe
Keyword(s):  
Finite Temperature ◽  
Chemical Potential ◽  
Sum Rules ◽  
Light Quark ◽  
Axial Vector ◽  
Heavy Ion ◽  
Qcd Sum Rules ◽  
Rho Meson ◽  
Ion Collisions ◽  
Rule Method

The method of QCD sum rules at finite temperature is reviewed, with emphasis on recent results. These include predictions for the survival of charmonium and bottonium states, at and beyond the critical temperature for deconfinement, as later confirmed by lattice QCD simulations. Also included are determinations in the light-quark vector and axial-vector channels, allowing analysing the Weinberg sum rules and predicting the dimuon spectrum in heavy-ion collisions in the region of the rho-meson. Also, in this sector, the determination of the temperature behaviour of the up-down quark mass, together with the pion decay constant, will be described. Finally, an extension of the QCD sum rule method to incorporate finite baryon chemical potential is reviewed.

scholarly journals Effects of Superstatistics on the Location of the Effective QCD Critical End Point

2019 ◽  
Vol 64 (8) ◽  
pp. 665
Author(s):  
A. Ayala ◽  
M. Hentschinski ◽  
L. A. Hernández ◽  
M. Loewe ◽  
R. Zamora
Keyword(s):  
Phase Diagram ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Chiral Symmetry Restoration ◽  
Interaction Volume ◽  
Qcd Phase Diagram ◽  
End Point ◽  
Ion Collisions ◽  
Effective Description

Effects of the partial thermalization during the chiral symmetry restoration at the finite temperature and quark chemical potential are considered for the position of the critical end point in an effective description of the QCD phase diagram. We find that these effects cause the critical end point to be displaced toward larger values of the temperature and lower values of the quark chemical potential, as compared to the case where the system can be regarded as completely thermalized. These effects may be important for relativistic heavy ion collisions, where the number of subsystems making up the whole interaction volume can be linked to the finite number of participants in the reaction.

DUALITY OF DYNAMICAL AND THERMAL DESCRIPTIONS IN PARTON DISTRIBUTION FUNCTIONS

2011 ◽  
Vol 26 (14) ◽  
pp. 1009-1016 ◽  
Author(s):  
J. CLEYMANS ◽  
G. I. LYKASOV ◽  
A. S. SORIN ◽  
O. V. TERYAEV
Keyword(s):  
Chemical Potential ◽  
Heavy Ion ◽  
Distribution Functions ◽  
Effective Width ◽  
Statistical Distributions ◽  
Free Nucleon ◽  
Parton Distribution Functions ◽  
Ion Collisions ◽  
Temperature Parameter ◽  
Statistical Form

We suggest a duality between the standard (dynamical) and statistical distributions of partons in the nucleons. The temperature parameter entering into the statistical form for the quark distributions is estimated. It is shown that the freeze-out temperature in central heavy-ion collisions at zero chemical potential or the effective width of the energy distribution of pions has a similar value which was estimated in this paper for the valence massless quarks in a free nucleon.

scholarly journals Flow and vorticity with varying chemical potential in relativistic heavy ion collisions

2020 ◽  
Vol 29 (01) ◽  
pp. 2050001
Author(s):  
Abhisek Saha ◽  
Soma Sanyal
Keyword(s):  
Shear Viscosity ◽  
Heavy Ion Collisions ◽  
Collision Energy ◽  
Chemical Potential ◽  
Transport Model ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Viscous Effects ◽  
Ion Collisions ◽  
Lower Collision

We study the vorticity patterns in relativistic heavy ion collisions with respect to the collision energy. The collision energy is related to the chemical potential used in the thermal — statistical models that assume approximate chemical equilibrium after the relativistic collision. We use the multiphase transport model (AMPT) to study the vorticity in the initial parton phase as well as the final hadronic phase of the relativistic heavy ion collision. We find that as the chemical potential increases, the vortices are larger in size. Using different definitions of vorticity, we find that vorticity plays a greater role at lower collision energies than at higher collision energies. We also look at other effects of the flow patterns related to the shear viscosity at different collision energies. We find that the shear viscosity obtained is almost a constant with a small decrease at higher collision energies. We also look at the elliptic flow as it is related to viscous effects in the final stages after the collision. Our results indicate that the viscosity plays a greater role at higher chemical potential and lower collision energies.

scholarly journals Centrality dependence of thermal freeze-out conditions at LHC in Pb+Pb collisions at sNN = 2.76TeV

2015 ◽  
Vol 30 (33) ◽  
pp. 1550167 ◽  
Author(s):  
Saeed Uddin ◽  
Inam-ul Bashir ◽  
Riyaz Ahmed Bhat ◽  
Waseem Bashir
Keyword(s):  
Experimental Data ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Collective Flow ◽  
Flow Profile ◽  
Alice Experiment ◽  
Ion Collisions ◽  
Momentum Spectra ◽  
Transverse Momentum Spectra ◽  
Freeze Out

We have analyzed the available midrapidity [Formula: see text] transverse momentum spectra of identified particles such as protons [Formula: see text], kaons [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] for different centralities of Pb+Pb collisions at the LHC energy [Formula: see text]. We have used our earlier proposed unified statistical thermal freeze-out model. The model incorporates the effect of nuclear transparency in such energetic collisions and the resulting asymmetry in the collective-flow profile along the longitudinal and the transverse directions. Our calculated results are found to be in good agreement with the experimental data measured by the ALICE experiment. The model calculation fits the experimental data for different particle species which provide thermal freeze-out conditions in terms of temperature and collective-flow parameters. The analysis shows a rise in the thermal freeze-out temperature and a mild decrease in the transverse collective-flow velocity as we go from central to the peripheral collisions. The baryon chemical potential is assumed to be nearly zero for the bulk of the matter [Formula: see text], a situation expected in the heavy ion collisions at LHC energies in the Bjorken approach owing to nearly complete nuclear transparency. The contributions from the decay of the heavier resonances are also taken into account in our calculations.

scholarly journals SKYRMION FORMATION IN 1+1 DIMENSIONS WITH CHEMICAL POTENTIAL

2006 ◽  
Vol 21 (06) ◽  
pp. 1199-1219 ◽  
Author(s):  
V. SUNIL KUMAR ◽  
BISWANATH LAYEK ◽  
AJIT M. SRIVASTAVA ◽  
SOMA SANYAL ◽  
VIVEK K. TIWARI
Keyword(s):  
Chemical Potential ◽  
Defect Density ◽  
Basic Mechanism ◽  
Heavy Ion ◽  
Tube Formation ◽  
Relativistic Heavy Ion Collisions ◽  
Potential Term ◽  
Ion Collisions ◽  
Spatially Varying ◽  
Superfluid Vortices

Formation of topological objects during phase transitions has been discussed extensively in literature. In all these discussions, defects and antidefects form with equal probabilities. In contrast, many physical situations, such as formation of baryons in relativistic heavy-ion collisions at present energies, flux tube formation in superconductors in the presence of external magnetic field, and formation of superfluid vortices in a rotating vessel, require a mechanism which can bias (say) defects over antidefects. Such a bias can crucially affect defect–antidefect correlations, apart from its effects on defect density. In this paper we initiate an investigation for the basic mechanism of biased formation of defects. For Skyrmions in 1+1 dimensions, we show that incorporation of a chemical potential term in the effective potential leads to a domain structure where order parameter is spatially varying. We show that this leads to biased formation of Skyrmions.

Electrical chemical potential andπ−-π+asymmetry in heavy-ion collisions

1994 ◽  
Vol 50 (4) ◽  
pp. 2232-2235 ◽  
Author(s):  
M. I. Gorenstein ◽  
H. G. Miller ◽  
R. M. Quick ◽  
Shin Nan Yang
Keyword(s):  
Heavy Ion Collisions ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Ion Collisions

scholarly journals A dynamical quasiparticle approach for the QGP bulk and transport properties

2016 ◽  
Vol 25 (07) ◽  
pp. 1642003 ◽  
Author(s):  
Hamza Berrehrah ◽  
Elena Bratkovskaya ◽  
Thorsten Steinert ◽  
Wolfgang Cassing
Keyword(s):  
Cross Sections ◽  
Degrees Of Freedom ◽  
Chemical Potential ◽  
Good Description ◽  
Charm Quark ◽  
Heavy Ion ◽  
Entropy Density ◽  
Self Energy ◽  
Ion Collisions ◽  
Transport Studies

The properties of quantum chromodynamics (QCD) nowadays are accessible by lattice QCD calculations at vanishing quark chemical potential [Formula: see text], but often lack a transparent physical interpretation. In this review, we report about results from an extended dynamical quasiparticle model (DQPM[Formula: see text]) in which the effective parton propagators have a complex self-energy that depends on the temperature [Formula: see text] of the medium as well as on the chemical potential [Formula: see text] and the parton three-momentum [Formula: see text] with respect to the medium at rest. It is demonstrated that this approach allows for a good description of QCD thermodynamics with respect to the entropy density, pressure, etc. above the critical temperature [Formula: see text] 158 MeV. Furthermore, the quark susceptibility [Formula: see text] and the quark number density [Formula: see text] are found to be reproduced simultaneously at zero and finite quark chemical potential. The shear and bulk viscosities [Formula: see text], and the electric conductivity [Formula: see text] from the DQPM[Formula: see text] also turn out in close agreement with lattice results for [Formula: see text] =0. The DQPM[Formula: see text], furthermore, allows to evaluate the momentum [Formula: see text], [Formula: see text] and [Formula: see text] dependencies of the partonic degrees of freedom also for larger [Formula: see text] which are mandatory for transport studies of heavy-ion collisions in the regime 5[Formula: see text]GeV [Formula: see text] 10[Formula: see text]GeV. We finally calculate the charm quark diffusion coefficient [Formula: see text] – evaluated from the differential cross-sections of partons in the medium for light and heavy quarks by employing the propagators and couplings from the DQPM – and compare it to the available lattice data. It is argued that the complete set of observables allows for a transparent interpretation of the properties of hot QCD.

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