scholarly journals Hadron Resonance Gas EoS and the Fluidity of Matter Produced in HIC

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Guruprasad Kadam ◽  
Swapnali Pawar
Keyword(s):  
Mass Spectrum ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Baryon Chemical Potential ◽  
Hadron Mass ◽  
Lattice Quantum ◽  
Hadron Gas ◽  
Ion Collision ◽  
Discrete Mass ◽  
The Ideal

We study the equation of state (EoS) of hot and dense hadron gas by incorporating the excluded volume corrections into the ideal hadron resonance gas (HRG) model. The total hadron mass spectrum of the model is the sum of the discrete mass spectrum consisting of all the experimentally known hadrons and the exponentially rising continuous Hagedorn states. We confront the EoS of the model with lattice quantum chromodynamics (LQCD) results at finite baryon chemical potential. We find that this modified HRG model reproduces the LQCD results up to T=160 MeV at zero as well as finite baryon chemical potential. We further estimate the shear viscosity within the ambit of this model in the context of heavy-ion collision experiments.

scholarly journals Hadron resonance gas with van der Waals interactions

2020 ◽  
Vol 29 (05) ◽  
pp. 2040002 ◽  
Author(s):  
Volodymyr Vovchenko
Keyword(s):  
Equation Of State ◽  
Van Der Waals ◽  
Heavy Ion ◽  
Van Der Waals Interactions ◽  
Excluded Volume ◽  
Heavy Ion Collision ◽  
Lattice Quantum Chromodynamics ◽  
Qcd Critical Point ◽  
Lattice Quantum ◽  
Ion Collision

An overview of a hadron resonance gas (HRG) model that includes van der Waals (vdW) interactions between hadrons is presented. Applications of the excluded volume HRG model to heavy-ion collision data and lattice quantum chromodynamics (QCD) equation of state are discussed. A recently developed quantum vdW HRG model is covered as well. Applications of this model in the context of the QCD critical point are elaborated.

scholarly journals Strangeness at high μB: Recent data from FOPI and HADES

2018 ◽  
Vol 171 ◽  
pp. 02001
Author(s):  
Yvonne Leifels
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Particle Production ◽  
Chemical Potential ◽  
Good Description ◽  
Branching Ratio ◽  
Heavy Ion ◽  
Nuclear Medium ◽  
Strangeness Production ◽  
Baryon Chemical Potential

Strangeness production in heavy-ion reactions at incident energies at or below the threshold in NN collisions gives access to the characteristics of bulk nuclear matter and the properties of strange particles inside the hot and dense nuclear medium, like potentials and interaction cross sections. At these energies strangeness is produced in multi-step processes potentially via excitation of intermediate heavy resonances. The amount of experimental data on strangeness production at these energies has increased substantially during the last years due to the FOPI and the HADES experiments at SIS18 at GSI. Experimental data on K+ and K0 production support the assumption that particles with an s quark feel a moderate repulsive potential in the nuclear medium. The situation is not that clear in the case of K-. Here, spectra and flow of K- mesons is influenced by the contribution of ø mesons which are decaying into K+K- pairs with a branching ratio of 48.9 %. Depending on incident energy upto 30 % of all K- mesons measured in heavyion collisions are originating from ø-decays. Strangeness production yields - except the yield of Ξ- are described by thermal hadronisation models. Experimental data not only measured for heavy-ion collisions but also in proton induced reactions are described with sets of temperature T and baryon chemical potential μb which are close to a universal freeze-out curve which is fitting also experimental data obtained at lower baryon chemical potential. Despite the good description of most particle production yields, the question how this is achieved is still not settled and should be the focus of further investigations.

scholarly journals Finite-volume effects on phase transition in the Polyakov-loop extended Nambu–Jona-Lasinio model with a chiral chemical potential

2017 ◽  
Vol 32 (13) ◽  
pp. 1750067 ◽  
Author(s):  
Zan Pan ◽  
Zhu-Fang Cui ◽  
Chao-Hsi Chang ◽  
Hong-Shi Zong
Keyword(s):  
Finite Volume ◽  
Chemical Potential ◽  
System Size ◽  
Heavy Ion ◽  
Polyakov Loop ◽  
End Point ◽  
Chemical Potentials ◽  
Ion Collision ◽  
Quark Flavors ◽  
Volume Effects

To investigate the finite-volume effects on the chiral symmetry restoration and the deconfinement transition for a quantum chromodynamics (QCD) system with [Formula: see text] (two quark flavors), we apply the Polyakov-loop extended Nambu–Jona-Lasinio model by introducing a chiral chemical potential [Formula: see text] artificially. The final numerical results indicate that the introduced chiral chemical potential does not change the critical exponents, but shifts the location of critical end point (CEP) significantly; the ratios for the chiral chemical potentials and temperatures at CEP, [Formula: see text] and [Formula: see text], are significantly affected by the system size [Formula: see text]. The behavior is that [Formula: see text] increases slowly with [Formula: see text] when [Formula: see text] is “large” and [Formula: see text] decreases first and then increases with [Formula: see text] when [Formula: see text] is “small.” It is also found that for a fixed [Formula: see text], there is a [Formula: see text], where the critical end point vanishes and the whole phase diagram becomes a crossover when [Formula: see text]. Therefore, we suggest that for the heavy-ion collision experiments, which is to study the possible location of CEP, the finite-volume behavior should be taken into account.

scholarly journals Chiral phase transition and kaon-to-pion ratios in the entanglement SU(3) PNJL model

2020 ◽  
Vol 229 (22-23) ◽  
pp. 3517-3536
Author(s):  
D. Blaschke ◽  
A. V. Friesen ◽  
Yu. L. Kalinovsky ◽  
A. Radzhabov
Keyword(s):  
Chemical Potential ◽  
Pion Mass ◽  
Heavy Ion ◽  
Bose Condensation ◽  
Chiral Phase ◽  
Qcd Phase Diagram ◽  
Scattering States ◽  
Meson Pole ◽  
Quark Models ◽  
Ion Collision

AbstractWithin the three-flavor PNJL and EPNJL chiral quark models we have obtained pseudoscalar meson properties in quark matter at finite temperature T and baryochemical potential μB. We compare the meson pole (Breit-Wigner) approximation with the Beth-Uhlenbeck (BU) approach that takes into account the continuum of quark-antiquark scattering states when determining the partial densities of pions and kaons. We evaluate the kaon-to-pion ratios along the (pseudo-)critical line in the T − μB plane as a proxy for the chemical freezeout line, whereby the variable x = T∕μB is introduced that corresponds to the conserved entropy per baryon as initial condition for the heavy-ion collision experiments. We present a comparison with the experimental pattern of kaon-to-pion ratios within the BU approach and using x-dependent pion and strange quark potentials. A sharp “horn” effect in the energy dependence K+∕π+ ratio is explained by the enhanced pion production at energies above √sNN=8 GeV, when the system enters the regime of meson dominance. This effect is in line with the enhancement of low-momentum pion spectra that is discussed as a precursor of the pion Bose condensation and entails the occurrence of a nonequilibrium pion chemical potential of the order of the pion mass. We elucidate that the horn effect is not related to the existence of a critical endpoint in the QCD phase diagram.

scholarly journals Fluctuations of conserved charges from imaginary chemical potential

2018 ◽  
Vol 175 ◽  
pp. 07036
Author(s):  
Jana N. Guenther ◽  
Szabolcs Borsányi ◽  
Zoltan Fodor ◽  
Sandor D. Katz ◽  
Attila Pásztor ◽  
...  
Keyword(s):  
Experimental Data ◽  
Chemical Potential ◽  
Heavy Ion ◽  
Higher Order ◽  
Order Derivative ◽  
Heavy Ion Collision ◽  
Lattice Calculation ◽  
Eighth Order ◽  
Conserved Charges ◽  
Ion Collision

When comparing lattice calculation to experimental data from heavy ion collision experiments, the higher order fluctuations of conserved charges are important observables. An efficient way to study these fluctuations is to determine them from simulations at imaginary chemical potential. In this talk we present results up to the six order derivative in μB (with up to eighth order included in the fit), calculated on a 483 × 12 lattice with staggered fermions using different values of μB while μS = μQ = 0.

Free energy of a baryon at finite temperatures and its implications to the heavy-ion collisions

2015 ◽  
Vol 30 (26) ◽  
pp. 1550130
Author(s):  
Minati Biswal ◽  
Sanatan Digal ◽  
P. S. Saumia
Keyword(s):  
Free Energy ◽  
Transition Temperature ◽  
Chemical Potential ◽  
Canonical Formalism ◽  
Heavy Ion ◽  
Polyakov Loop ◽  
Heavy Ion Collision ◽  
Hydrodynamic Simulations ◽  
Ion Collisions ◽  
Ion Collision

We study the free energy per baryon using canonical formalism in the Polyakov loop Nambu–Jona-Lasinio model with imaginary chemical potential. We find that the free energy decreases rapidly with temperature around the transition temperature. This result coupled with the heavy-ion collision geometry leads to the creation of a free energy well for the baryons. We study the time evolution of this free energy well using hydrodynamic simulations and discuss the implications of this free energy well on the dynamics of the baryons.

scholarly journals STRONGLY INTERACTING MATTER AT FINITE CHEMICAL POTENTIAL: HYBRID MODEL APPROACH

2013 ◽  
Vol 28 (14) ◽  
pp. 1350051 ◽  
Author(s):  
P. K. SRIVASTAVA ◽  
C. P. SINGH
Keyword(s):  
Hybrid Model ◽  
Chemical Potential ◽  
Gluon Plasma ◽  
Model Description ◽  
Baryon Chemical Potential ◽  
Qcd Phase Diagram ◽  
Strongly Interacting ◽  
Hadron Gas ◽  
Quasiparticle Model ◽  
Model Approach

Search for a proper and realistic equation of state (EOS) for strongly interacting matter used in the study of the QCD phase diagram still appears as a challenging problem. Recently, we constructed a hybrid model description for the quark–gluon plasma (QGP) as well as hadron gas (HG) phases where we used an excluded volume model for HG and a thermodynamically consistent quasiparticle model for the QGP phase. The hybrid model suitably describes the recent lattice results of various thermodynamical as well as transport properties of the QCD matter at zero baryon chemical potential (μB). In this paper, we extend our investigations further in obtaining the properties of QCD matter at finite value of μB and compare our results with the most recent results of lattice QCD calculation.

scholarly journals Polarization tensor of magnetized quark-gluon plasma at nonzero baryon density

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Xinyang Wang ◽  
Igor Shovkovy
Keyword(s):  
Quark Gluon Plasma ◽  
Chemical Potential ◽  
Photon Emission ◽  
Absorptive Part ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Photon Production ◽  
Polarization Tensor ◽  
Baryon Chemical Potential ◽  
Wide Range

AbstractWe derive a general expression for the absorptive part of the one-loop photon polarization tensor in a strongly magnetized quark-gluon plasma at nonzero baryon chemical potential. To demonstrate the application of the main result in the context of heavy-ion collisions, we study the effect of a nonzero baryon chemical potential on the photon emission rate. The rate and the ellipticity of photon emission are studied numerically as a function the transverse momentum (energy) for several values of temperature and chemical potential. When the chemical potential is small compared to the temperature, the rates of the quark and antiquark splitting processes (i.e., $$q\rightarrow q +\gamma $$ q → q + γ and $${\bar{q}}\rightarrow {\bar{q}} +\gamma $$ q ¯ → q ¯ + γ , respectively) are approximately the same. However, the quark splitting gradually becomes the dominant process with increasing the chemical potential. We also find that increasing the chemical potential leads to a growing total photon production rate but has only a small effect on the ellipticity of photon emission. The quark-antiquark annihilation ($$q+{\bar{q}}\rightarrow \gamma $$ q + q ¯ → γ ) also contributes to the photon production, but its contribution remains relatively small for a wide range of temperatures and chemical potentials investigated.

scholarly journals Exploring hot and dense QCD matter with HADES

2020 ◽  
Vol 1643 (1) ◽  
pp. 012012
Author(s):  
Georgy Kornakov
Keyword(s):  
Chemical Potential ◽  
Thermal Emission ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Baryon Chemical Potential ◽  
Qcd Phase Diagram ◽  
Test Models ◽  
Particle Spectra ◽  
Strangeness Content ◽  
Dilepton Spectrum

Abstract Experiments at snn s NN = 2 − 3 3 GeV provide the lowest energy point of the global effort made by the heavy-ion community in order to map the QCD phase diagram. This correspond to the highest baryon chemical potential, 700-900 MeV according to the universal freeze-out curve, and temperatures of the fireball of 60-80 MeV. The formed matter can be characterized in terms of particle spectra, fluctuations and correlations. The dilepton spectrum is dominated by thermal emission from the medium and it is sensitive to in medium hadron properties. Strangeness production occurs below the free nucleon-nucleon threshold and it is a sensitive probe to test models of strangeness propagation in matter and its coupling to baryons. Data show a common scaling of measured yields as a function of number of participating nucleons independently on the strangeness content or mass of the hadron. Strangeness propagation in cold nuclear matter produced in pion induced reactions on heavy and light targets shows a significant absorption of negative kaons in heavy targets as well as a similar behaviour of ϕ indicating a strong coupling of ϕ with nucleons. Two-pion correlations, flow harmonics, fluctuations are explored as well in order to further pin down the properties of the created matter.

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