scholarly journals From Heavy-Ion Collisions to Compact Stars: Equation of State and Relevance of the System Size

Universe ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 14 ◽  
Author(s):  
Sylvain Mogliacci ◽  
Isobel Kolbé ◽  
W. Horowitz
Keyword(s):  
Equation Of State ◽  
Degrees Of Freedom ◽  
Compact Star ◽  
Relativistic Quantum ◽  
Finite Size ◽  
Baryon Number ◽  
System Size ◽  
Heavy Ion ◽  
Compact Stars ◽  
Heavy Ion Physics

In this article, we start by presenting state-of-the-art methods allowing us to compute moments related to the globally conserved baryon number, by means of first principle resummed perturbative frameworks. We focus on such quantities for they convey important properties of the finite temperature and density equation of state, being particularly sensitive to changes in the degrees of freedom across the quark-hadron phase transition. We thus present various number susceptibilities along with the corresponding results as obtained by lattice quantum chromodynamics collaborations, and comment on their comparison. Next, omitting the importance of coupling corrections and considering a zero-density toy model for the sake of argument, we focus on corrections due to the small size of heavy-ion collision systems, by means of spatial compactifications. Briefly motivating the relevance of finite size effects in heavy-ion physics, in opposition to the compact star physics, we present a few preliminary thermodynamic results together with the speed of sound for certain finite size relativistic quantum systems at very high temperature.

scholarly journals Toward a unified equation of state for multi-messenger astronomy

2020 ◽  
Vol 643 ◽  
pp. A82 ◽  
Author(s):  
M. Marczenko ◽  
D. Blaschke ◽  
K. Redlich ◽  
C. Sasaki
Keyword(s):  
Equation Of State ◽  
Degrees Of Freedom ◽  
Chiral Symmetry Breaking ◽  
Light Quark ◽  
Mean Field ◽  
Heavy Ion ◽  
Compact Stars ◽  
Model Parameters ◽  
Nucleon Matter ◽  
Ion Collision

Aims. We aim to present a first step in developing a benchmark equation-of-state (EoS) model for multi-messenger astronomy that unifies the thermodynamics of quark and hadronic degrees of freedom. Methods. A Lagrangian approach to the thermodynamic potential of quark-meson-nucleon matter was used. In this approach, dynamical chiral-symmetry breaking is described by the scalar mean-field dynamics coupled to quarks and nucleons and their chiral partners, whereby its restoration occurs in the hadronic phase by parity doubling, as well as in the quark phase. Quark confinement was achieved by an auxiliary scalar field that parametrizes a dynamical infrared cut-off in the quark sector, serving as an ultraviolet cut-off for the nucleonic phase space. The gap equations were solved for the isospin-symmetric case, as well as for neutron star (NS) conditions. We also calculated the mass-radius (MR) relation of NSs and their tidal deformability (TD) parameter. Results. The obtained EoS is in accordance with nuclear matter properties at saturation density and with the flow constraint from heavy ion collision experiments. For isospin-asymmetric matter, a sequential occurrence of light quark flavors is obtained, allowing for a mixed phase of chirally-symmetric nucleonic matter with deconfined down quarks. The MR relations and TDs for compact stars fulfill the constraints from the latest astrophysical observations for PSR J0740+6620, PSR J0030+0451, and the NS merger GW170817, whereby the tension between the maximum mass and compactness constraints rather uniquely fixes the model parameters. The model predicts the existence of stars with a core of chirally restored but purely hadronic (confined) matter for masses beyond 1.8 M⊙. Stars with pure-quark matter cores are found to be unstable against the gravitational collapse. This instability is shifted to even higher densities if repulsive interactions between quarks are included.

scholarly journals Quark Number Susceptibilities and Equation of State in QCD at Finite μB

Proceedings ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 5
Author(s):  
Saumen Datta ◽  
Rajiv Gavai ◽  
Sourendu Gupta
Keyword(s):  
Equation Of State ◽  
Taylor Series ◽  
Chemical Potential ◽  
Baryon Number ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collider ◽  
Quark Number ◽  
Monte Carlo Studies ◽  
Essential Input ◽  
Beam Energy Scan

One of the main goals of the cold baryonic matter (CBM) experiment at FAIR is to explore the phases of strongly interacting matter at finite temperature and baryon chemical potential μ B . The equation of state of quantum chromodynamics (QCD) at μ B > 0 is an essential input for the CBM experiment, as well as for the beam energy scan in the Relativistic Heavy Ion Collider(RHIC) experiment. Unfortunately, it is highly nontrivial to calculate the equation of state directly from QCD: numerical Monte Carlo studies on lattice are not useful at finite μ B . Using the method of Taylor expansion in chemical potential, we estimate the equation of state, namely the baryon number density and its contribution to the pressure, for two-flavor QCD at moderate μ B . We also study the quark number susceptibilities. We examine the technicalities associated with summing the Taylor series, and explore a Pade resummation. An examination of the Taylor series can be used to get an estimate of the location of the critical point in μ B , T plane.

scholarly journals Finite-size behaviour of a critical related observable

Open Physics ◽  
2012 ◽  
Vol 10 (6) ◽  
Author(s):  
Wu Yuanfang ◽  
Chen Lizhu ◽  
Pan Xue ◽  
Shao Ming ◽  
Xiaosong Chen
Keyword(s):  
Fixed Point ◽  
Heavy Ion Collisions ◽  
Finite Size ◽  
System Size ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Charge Fluctuations ◽  
Qcd Critical Point ◽  
Ion Collisions ◽  
Straight Line

AbstractAccounting for the influence of system size in relativistic heavy ion collisions, the finite-size form of a critical related observable is suggested. The fixed-point and straight line methods are proposed in exploring the QCD critical point and phase boundary in relativistic heavy ion collisions. As an application, the finitesize behaviour of the ratios of higher net-proton cumulants, dynamical electric charge fluctuations, and transverse momentum correlations in Au + Au collisions at RHIC are examined.

scholarly journals Deconfinement signals from pulsar timing

2000 ◽  
Vol 177 ◽  
pp. 603-604 ◽  
Author(s):  
Hovik Grigorian ◽  
Gevorg Poghosyan ◽  
Edvard Chubarian ◽  
David Blaschke
Keyword(s):  
General Relativity ◽  
Quark Matter ◽  
Compact Star ◽  
Baryon Number ◽  
Rotational Frequency ◽  
Compact Stars ◽  
Pulsar Timing

AbstractThe occurence of a quark matter core in rotating compact stars has been investigated within general relativity as a function of both the rotational frequency and the total baryon number. We demonstrate that the deviation of the braking index fromn= 3 signals not only the occurence but also the size of a quark matter core in a pulsar. We suggest that in systems with mass accretion onto a rapidly rotating compact star a spin-down to spin-up transition might signal a deconfinement transition in its interior.

scholarly journals Influence of the equation of state on a compact star made of hidden-sector nucleons

2020 ◽  
Vol 2020 (3) ◽  
Author(s):  
Shinji Maedan
Keyword(s):  
Equation Of State ◽  
Cold Dark Matter ◽  
Compact Star ◽  
Mean Field ◽  
Field Approximation ◽  
Compact Stars ◽  
Mean Field Approximation ◽  
Effective Theory ◽  
Hidden Sector ◽  
Two Parameters

Abstract We study a compact star made of degenerate hidden-sector nucleons which will be a candidate for cold dark matter. A hidden sector like quantum chromodynamics is considered, and as the low-energy effective theory we take the (hidden-sector) $ SU(2) $ chiral sigma model including a hidden-sector vector meson. With the mean field approximation, we find that one can treat the equation of state (EOS) of our model analytically by introducing a variable which depends on the Fermi momentum. The EOS is specified by the two parameters $ C'_{\sigma} $, $ C'_{\omega} $, and we discuss how these parameters affect the mass–radius relation for a compact star as well as the EOS. The dependence of the maximum stable mass of compact stars on the parameter $ C'_{\sigma} $ will also be discussed.

scholarly journals QUARK–DIQUARK EQUATIONS OF STATE MODELS: THE ROLE OF INTERACTIONS

2003 ◽  
Vol 12 (03) ◽  
pp. 519-526 ◽  
Author(s):  
J. E. HORVATH ◽  
G. LUGONES ◽  
J. A. DE FREITAS PACHECO
Keyword(s):  
Equation Of State ◽  
Boundary Conditions ◽  
Neutron Stars ◽  
Hard Sphere ◽  
Degrees Of Freedom ◽  
Equations Of State ◽  
Compact Star ◽  
Star Models ◽  
State Models

Recent observational data suggests a high compacticity (the quotient M/R) of some "neutron" stars. Motivated by these works we revisit models based on quark–diquark degrees of freedom and address the question of whether that matter is stable against diquark disassembling and hadronization within the different models. We find that equations of state modeled as effective λϕ4 theories do not generally produce stable self-bound matter and are not suitable for constructing very compact star models, that is the matter would decay into neutron matter. We also discuss some insights obtained by including hard sphere terms in the equation of state to model repulsive interactions. We finally compare the resulting equations of state with previous models and emphasize the role of the boundary conditions at the surface of compact self-bound stars, features of a possible normal crust of the latter and related topics.

STRONGLY INTERACTING QGP AND QUARKONIUM SUPPRESSION AT RHIC AND LHC ENERGIES

2012 ◽  
Vol 27 (02) ◽  
pp. 1250009 ◽  
Author(s):  
VINEET AGOTIYA ◽  
LATA DEVI ◽  
UTTAM KAKADE ◽  
BINOY KRISHNA PATRA
Keyword(s):  
Equation Of State ◽  
Degrees Of Freedom ◽  
Heavy Ion ◽  
Gluon Plasma ◽  
Relativistic Heavy Ion Collisions ◽  
Strongly Coupled ◽  
Cornell Potential ◽  
Ion Collisions ◽  
Strongly Interacting ◽  
Strongly Coupled Plasma

We have developed an equation of state for strongly interacting quark–gluon plasma (QGP) in the framework of strongly coupled plasma with appropriate modifications to take account of color and flavor degrees of freedom and the interactions among themselves. For this purpose we used the effective potential to improve the plasma parameter (Γ) by correcting the full Cornell potential with a dielectric function embodying the effects of the deconfined medium and not its Coulomb part alone and obtain the equation of state in terms of Γ. Our results on thermodynamic observables viz. pressure, energy density, speed of sound etc. nicely fit to the results of lattice equation of state for gluon, massless as well massive flavored plasma. We have then employed our equation of state to estimate the quarkonium suppression in an expanding QGP produced in the relativistic heavy-ion collisions. We have found that our predictions matches with the recent PHENIX data on the centrality dependence of J/ψ suppression in Au+Au collisions at BNL RHIC within the limit of other uncertainties. We have also predicted for the ϒ suppression in Pb+Pb collisions at LHC energy which could be tested in the ALICE experiments at CERN LHC.

Effects of strong magnetic fields in dense stellar matter

2013 ◽  
Vol 9 (S302) ◽  
pp. 439-440
Author(s):  
A. Lavagno ◽  
F. Lingua
Keyword(s):  
Equation Of State ◽  
Magnetic Fields ◽  
Degrees Of Freedom ◽  
Compact Star ◽  
Relativistic Equation ◽  
Bulk Properties ◽  
Strong Magnetic Fields ◽  
Stellar Matter ◽  
Nuclear Equation Of State

AbstractWe study the effects of strong magnetic fields in dense stellar matter within an effective relativistic equation of state with the inclusion of hyperons and Δ(1232)-isobar degrees of freedom. The effects of high magnetic field interactions significantly affect the nuclear equation of state and the macroscopic properties of the star. In this framework we investigate the role of the presence of the Δ-isobars degrees of freedom in structure and in the bulk properties of the compact star.

PARTONIC EQUATION OF STATE IN HIGH-ENERGY NUCLEAR COLLISIONS

2007 ◽  
Vol 16 (03) ◽  
pp. 715-727 ◽  
Author(s):  
NU XU
Keyword(s):  
Equation Of State ◽  
Heavy Ion Collisions ◽  
Degrees Of Freedom ◽  
Collective Motion ◽  
Radial Flow ◽  
Heavy Ion ◽  
High Energy ◽  
Experimental Results ◽  
Nuclear Collisions ◽  
Ion Collisions

After a brief introduction to the physics of high-energy nuclear collisions, we will present recent experimental results that are closely connected to the properties of the matter produced in Au + Au collisions at RHIC. Collective motion with parton degrees of freedom is called partonic collectivity. We will focus on collective observables such as transverse radial flow and elliptic flow. With experimental observations, we will demonstrate that collectivity is developed prior to the hadronic stage in heavy ion collisions at RHIC.

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