The results from the analysis of fluctuations and correlations can help to discover the
critical point of strongly interacting matter. In the NA61/SHINE experiment the strategy
of locating the critical point relies on performing a two dimensional phase diagram
(T-mu_B) scan by measurements of fluctuations and correlations in proton-proton,
proton-nucleus and nucleus-nucleus interactions as a...
One of the motivations for the RHIC beam energy scan program was its capability of providing data for the determination of the temperature- and baryon-density dependence of QGP transport coefficients, such as the specific shear viscosity. This task is complicated by the rich set phenomena that computational models commonly used for the determination of the transport coefficients need to...
In this talk, I will first summarize the critical behavior of fluctuations of conserved charges expected in the vicinity of the chiral phase boundary. Then, I will show how the finite quark mass or finite volume modifies the divergent cumulants in QCD-like model calculations.Particular emphasis will be put on the importance of the regular contribution to the fluctuations when the singular part...
In the framework of an SU(3) (axial)vector meson extended linear sigma model with additional constituent quarks and Polyakov loops, we investigate the effects of (axial)vector mesons on the chiral phase transition. The parameters of the Lagrangian are set at zero temperature and we use a hybrid approach where in the effective potential the constituent quarks are treated at one-loop level and...
New results of the NA61/SHINE and HADES collaborations, as well as the updated data from NA49, and the existing data from other collaborations are analyzed within the transport models and the hadron resonance gas (HRG) statistical model. The chemical freeze-out parameters in $p+p$ interactions and central $A+A$ collisions are found and compared with each other in the $\sqrt{s_{NN}}$ = 3.2−17.3...
Pion production in the backward direction in the target rest frame is considered
in proton-nucleus (p+A) collisions. Pions outside the kinematical boundary of
proton-nucleon (p+N) collisions, the so called cumulative effect, is studied.
Basic restrictions on the energy of pions emitted in the backward direction in
p+N and p+A reactions are considered. These are restrictions that follow...
We study inverse magnetic catalysis in the Nambu--Jona-Lasinio model beyond mean field approximation. The feed-down from mesons to quarks is embedded in an effective coupling constant at finite temperature and magnetic field. While the magnetic catalysis is still the dominant effect at low temperature, the meson dressed quark mass drops down with increasing magnetic field at high temperature...
A power expansion scheme is set up to determine the Wigner function that satisfies the quantum kinetic equation for spin-1/2 charged fermions in a background electromagnetic field. Vector and axial-vector current induced by magnetic field and vorticity are obtained simultaneously from the Wigner function. The chiral magnetic and vortical effect and chiral anomaly are shown as natural...
The preliminary centrality determination procedure and charge hadron multiplicity fluctuations are investigated in the new Ar+Sc data at 13A, 19A, 30A, 40A, 75A, 150A GeV/c with NA61/SHINE at the SPS. The centrality analysis is based on nucleon-spectator energy in the forward hemisphere from the Projectile spectator detector. The scaled variance for all, negatively and positively charged...
We study a charm quark diffusion coefficient with nonzero momentum
correlator on the quenched lattice. Starting from rather general requirements on the spectral function, we derive inequalities to constrain the value of the diffusion coefficient. These inequalities have quantities which can be measured on the lattice
from temporal correlator with nonzero momentum. Using the inequalities and...
The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study the properties of the onset of deconfinement. For these goals a scan of the two dimensional phase diagram (T-$\mu_{B}$) is being performed at the SPS by measurements of hadron production in proton-nucleus and nucleus-nucleus interactions as a function of collision energy and system size....
One of remarkable features in the expected structure of the QCD phase diagram is the existence of QCD critical point (CP), which is the end point of the phase boundary of the first-order between the hadronic phase and the QGP phase. At the CP, the phase transition becomes second order, and thus there should be gapless and long-life modes called the soft modes, which govern the low-energy...
The aim of the NA61/SHINE ion programme is to explore the QCD phase diagram within the range of thermodynamical variables accessible by the SPS. In addition the experiment provides precision hadron production measurements for description of the neutrino beam of the T2K experiment at J-PARC and for simulation of cosmic-ray showers for the Pierre Auger Observatory and KASCADE experiments. The...
Model parameter free investigations of Yang-Mills theory and quenched QCD in the vacuum are presented as a necessary prerequisitve for corresponding investigations of the QCD phase structure with the functional renormalisation group equation. Preliminary results for Yang-Mills theory at finite temperature are discussed. Finally, a phenomenological application of the vacuum results to the...
The investigation of preliminary results for mean negatively charged pion multiplicities $\langle \pi^- \rangle$ from Ar+Sc collisions is the main topic of the talk.
The data has been taken recently by the NA61/SHINE collaboration for a wide range of momenta - 13, 19, 30, 40, 75 and 150 A GeV/c. Starting with rapidity distibution of differential spectra
$\frac{dn}{dy}$ extrapolated to...
Recent developments in anisotropic hydrodynamics will be reviewed.
We analyze the directed flow ($v_1$) of protons and pions
in high-energy heavy-ion collisions in the incident energy range
from $\sqrt{s_{{\scriptscriptstyle NN}}}=7.7$ GeV to 27 GeV
within a microscopic transport model [1].
Standard hadronic transport approaches do not explain the collapse of directed flow below
$\sqrt{s_{{\scriptscriptstyle NN}}}\simeq 20$ GeV.
By contrast, when we take...
We study the formation of collective flow vorticity in non-central heavy ion collisions at RHIC Beam Energy Scan collision energy range, $\sqrt{s_{\rm NN}}=7.7\dots 200$ GeV with state-of-the-art viscous hydro model, vHLLE+UrQMD. With the model adjusted to approach the experimental data for rapidity, transverse momentum distributions and elliptic flow of produced hadrons, we explore the...
A biref summary on the recent result on compact star equation of state will be presented. I summarize the directions and activities of the NewCompStar working group on the physics of the strong interaction in cold dense nuclear and QCD medium exists in compact stars.
This talk will describe the continuing development of a consistent
picture of the liquid interiors of neutron stars, driven by three
recent advances: observations of heavy neutron stars with masses ~2.0
solar masses; determinations of masses and radii simultaneously for an
increasing number of neutron stars; and an emerging understanding in
QCD of how nuclear matter can turn into deconfined...
We delineate properties of cold, dense QCD matter through equations of state supposed from observational constraints on neutron stars.
We address holographically (i) an emulation of deconfinement upon temperature increase as
sequential or instanteneous melting (disappearence) of normalizable eigenmodes of hadron states with a Regge type spectrum in vacuum, and (ii) the phase diagram within the updated DeWolfe-Gubser-Rosen model. Photon emission rates are calculated and found to map out the pecularities (CEP and first-order...
The CBM Experiment is one of the main four scientific pillars of the
new Facility for Antiproton and Ion Research (FAIR). Its main
objective is the study of the QCD phase diagram in the region of high
baryon-densities. With nucleus-nucleus collisions at the SIS100
accelerator at beam energies up to 14 A GeV strongly interacting
matter with densities about 10 times as high as normal...
Data on particle production in heavy ion collisions in the energy regime of 1-2 A GeV have been collected over almost three decades now. As most of the newly created hadrons are produced below or slightly above their free NN-thresholds, data are usually interpreted with the help of phenomenological models, rather than comparing to elementary reference measurements. Driven by advance in...
The computation of single particle spectral functions and transport coefficients with functional continuum methods is discussed. Results are presented for quark and meson, and glue ball spectral functions, as well as the temperature-dependent shear viscosity over entropy ratio.
Fluctuation observables in relativistic heavy ion collisions measured by event-by-event analysis are important observables for the study of thermodynamics in primordial stage. In this talk, I will discuss some problems which have to be considered seriously when one compares the experimental results on fluctuations with theoretical study. In particular, I will discuss (1)non-equilibrium...
Electromagnetic probes are radiated during the whole time evolution of a heavy-ion collision. They decouple from the collision zone once they are produced and carry valuable information about the properties of matter created inside the hot and dense fireball to the detector.
In particular, the yield of low-mass dileptons was identified to be sensitive to the fireball lifetime, while the slope...
Electromagnetic radiation in heavy-ion collisions at SIS18, FAIR, SPS, RHIC and LHC energies is studied within an approach which uses coarse-grained transport simulations to calculate thermal dilepton and photon emission applying in-medium spectral functions from hadronic many-body theory and partonic production rates based on lattice calculations. The microscopic output from the...
We carry out numerical evaluations of the motion of classical particles in Minkowski space ${\cal{M}}^4$ which are confined to the inside of a bag. In particular, we analyze the structure of the paths evolving from the breaking of the dilatation symmetry, the conformal symmetry and the combination of both together. The confining forces arise directly from the corresponding nonconserved...
We analyze the production rate of photons from the deconfined medium with a quark propagator obtained from a lattice QCD numerical simulation. We calculate the production rates non-perturbatively at two temperatures above $T_{\rm c}$. The photon-quark vertex is determined gauge-invariantly so as to satisfy the Ward-Takahashi identity. It is found that the vertex correction modifies spectra...
I look back at the early results of S+S collisions at 200 A GeV and related theoretical data analysis of more than 20 years ago, and compare these results with those we have since obtained in Pb-Pb reactions at SPS and LHC. The key signatures, strangeness and multistrange antibaryons, as well as entropy content of this small system do indicate development of conditions that are today...
We study the relation between quark confinement and chiral symmetry breaking, and investigate interplay between confinement/deconfinement and chiral properties at finite temperatures. We analytically derive some relations of the Polyakov loop or its fluctuations with Dirac eigenmodes in temporally odd-number lattice QCD [1,2]. For the these quantities related to confinement, the contribution...
The dependence of particle production on the size of the colliding nuclei is
analysed in terms of the thermal model using the canonical ensemble.
The concept of strangeness correlation in clusters of sub-volume $V_C$ is used
to account for the suppression of strangeness.
A systematic analysis is presented of the predictions of the thermal model
for particle production in collisions of small...
The Nuclotron-based Ion Collider Facility (NICA) project is now under active realization at the Joint Institute for Nuclear Research (JINR, Dubna). The main goal of the project is an experimental study of hot and dense strongly interacting matter in heavy ion (up to Au) collisions at centre-of-mass energies up to 11 GeV per nucleon. Two modes of the operation are foreseen, collider mode and...
We investigate the relation between quark confinement and chiral symmetry breaking in the finite-temperature lattice QCD. First of all, we derive analytical formulae to express the Polyakov loop and its fluctuations in terms of the Dirac eigenmodes[1-3]. Based on the analytical formulae, it is shown that the low-lying Dirac modes have little contribution to the quantities such as the Polyakov...
An effective model for low-energy QCD thermodynamics is presented which provides a microscopic interpretation of the transition from a gas of hadron resonances to the quark-gluon plasma by Mott dissociation of hadrons. The self consistent approximation scheme of the Φ-derivable approach is applied to describe the thermodynamics of the Polyakov loop extended Nambu–Jona-Lasinio (PNJL) model...
The deconfinement transition at vanishing chemical potential can be reliably studied by lattice simulations and its general features are by now well known. On the contrary, what happens at finite density is still largely unknown and in this talk I will review the results obtained in the last year regarding the dependence, for small density, of the (pseudo)critical temperature on the baryonic...
NA61/SHINE at the CERN SPS is a fixed-target experiment pursuing a rich physics program including measurements for heavy ion, neutrino and cosmic ray physics. The main goal of the ion program is to study the properties of the onset of deconfinement and to search for the signatures of the critical point. Specific property of the critical point – increase in the correlation length – makes...
We investigate the kurtosis of the net-proton number and the chiral order parameter within the model of nonequilibrium chiral fluid dynamics for a crossover scenario near the critical point. Our model describes the interplay between a dynamical order parameter and a quark-gluon fluid during the expansion of the hot fireball created in a heavy-ion collision. A subsequent particlization process...
We present a thermodynamical analysis of the nonextensive, QCD-based, Nambu - Jona-Lasinio model (NJL) of strongly interacting matter in the critical region. It is based on the nonextensive generalization of the Boltzmann-Gibbs (BG) statistical mechanics, used in the NJL model, to its nonextensive version. This can be introduced in different ways, depending on different possible choices of the...
Extensive measurements of azimuthal anisotropy
in heavy-ion collisions, have provided invaluable
insights on the expansion dynamics and the transport properties of the
strongly interacting matter produced in collisions at RHIC and the LHC.
However, recently a number of measurements from high-multiplicity collisions
in small systems at RHIC and LHC, such as p+p, p+A, or d+Au, have...
In recent years there has been much interest in the study of graphene, which is a 2-dimensional crystal of carbon atoms that exhibits many interesting electronic properties and quantum effects. The dynamical generation of a gap would cause the system to undergo a phase transition to an insulating state. From a technological point of view, a finite gap would make graphene more promising as a...
Dileptons are a unique probe to study microscopic properties of nuclear matter under extreme
conditions of temperature and density achieved in heavy-ion collisions. The low-mass excess radiation
(above cocktail) observed from SIS to top RHIC energies is well understood theoretically in terms of
strict VMD assuming strong broadening of the in-medium rho spectral function. This broadening...
We simulate the kinetics of the chiral phase transition in hot and dense
strongly interacting matter within a novel kinetic-theory approach. Employing
an effective linear $\sigma$ model for quarks, $\sigma$ mesons, and
pions we treat the quarks within a test-particle ansatz for solving the
Boltzmann transport equation and the mesons in terms of classical
fields. The decay-recombination...
The importance of the RHIC beam energy scan program is that comparing results at different energies (varied in the region where the transition from hadronic to quark matter is expected to occur) allows us to investigate the structure of QCD matter, and the quark-hadron transition. One of the best tools to gain information about the (soft) particle-emitting source is the measurement of...
Non-critical thermal fluctuations are important baselines in search of the critical point for the RHIC beam energy scan program. In this talk, we present our investigations on the non-critical baselines of cumulants of (net-conserved) charge distributions in relativistic heavy ion collisions. By deriving a general formula of multiplicity distribution in connect with the method used in...
The existence of the inhomogeneous chiral phase, where the chiral condensate is spatially modulated has been discussed from some effective model analysis.
The phase seems to emerge in compact stars because it appears around the conventional chiral phase transition line in the QCD phase diagram.
Assuming an inhomogeneous configuration called "dual chiral density wave (DCDW)", where both scalar...
Many data in the High Energy Physics are, in fact, sample means. It is shown that
when this exact meaning of the data is taken into account and the most weakly
bound states are removed from the hadron resonance gas, the acceptable fit to the
whole spectra of pions, kaons and protons measured at midrapidity in central Pb-Pb
collisions at $\sqrt{s_{NN}} = 2.76$ TeV is obtained. The invariant...
Using a bottom-up gauge gravity constructions, relaxation rates of strongly coupled field theories are computed. A variety of phase structures are considered, from a crossover up to a first order phase transition. It is established that near the transition the applicability of a hydrodynamic description breaks down at lower momenta than in the conformal case. In the case of the first order...
Starting from the (Polyakov-) Nambu-Jona-Lasinio Lagrangian, (P)NJL, we formulate a transport theory which allows for describing the expansion of a quark-antiquark plasma and the subsequent transition to the hadronic world ---without adding
any new parameter to the standard (P)NJL approach, whose parameters are fixed to vacuum physics. This transport theory can be used to describe...
Recently, the STAR beam energy scan (BES) measured the multiplicity distributions of net protons with the maximum transverse momentum extended from 0.8 GeV to 2 GeV. The related higher cumulants (moments) present large deviations from the poisson baselines, showing the potential of discovery the QCD critical point in experiment.
In this talk, we introduce a freeze-out scheme for the...
The presence of collective expansion in small collision is discussed.
Approaches based on relativistic hydrodynamics are compared to existing data.
Possibilities to study fluctuations in the interaction region in small collision systems
are described.
While the crucial role of gauge topology was recognized from 1970’s,
confinement was associated with monopoles and chiral symmetry breaking with instantons.
Recognizing presence of non-zero holonomy, van Baal and others discovered
splitting of the instantons into their constituents — the instanton-dyons.
Several groups now work out properties of their ensembles, which generate
both
the...
Non-equilibrium evolution of cumulants of critical fluctuations for space-time trajectories on the cross-over side of the QCD phase diagram we be discussed in detail. Memory effects are important. Utilizing a simple model of the space-time evolution of a heavy-ion collision, we demonstrate that, depending on the relaxation rate of critical fluctuations, Skewness and Kurtosis can differ...
We compare the low eigenvalue spectra of the Overlap Dirac
operator on two sets of configurations at $\mu_I/mu_I^c = 0.5$ and $1.5$ generated with dynamical staggered fermions at these isospin chemical potential on $24^3 \times 6$ lattices. We find very small changes in the number of zero modes and low lying modes across the transition which is in stark contrast with those across the...
We apply the wounded quark model to particle production and properties of the initial fireball in A+A, p+A, and p+p collisions at the Large Hadron Collider (LHC). We find uniformity of the approach, as similar production of initial entropy per source
is needed to explain particle production in all studied reactions and at all centralities. We also investigate event-by-event initial...
Compressed Baryonic Matter experiment (CBM) at FAIR has a potential of discoveries in the area of QCD phase diagram with high net baryon densities and moderate temperatures. Anisotropic transverse flow is one of the key observables to study the properties of matter created in a heavy-ion collisions.
CBM performance for anisotropic flow measurements is studied with Monte-Carlo simulations of...
The size and evolution of the medium created in a heavy-ion collision depends on collision geometry. Experimentally collisions are characterized by the measured particles multiplicities around midrapidity or energy measured in the forward rapidity region, which is sensitive to the spectator fragments. In the CBM experiment the multiplicity of produced particles is measured with the silicon...
The aim of our work is to develop a unified equation of state (EoS) for nuclear and quark matter for a wide range in temperature, density and isospin so that it becomes applicable for heavy-ion collisions as well as for the astrophysics of neutron stars, their mergers and supernova explosions. As a first step, we use improved EoS for the hadronic and quark matter phases and join them via...
We present an effective model for low-energy QCD thermodynamics which provides a microscopic interpretation of the transition from a gas of hadron resonances to the quark-gluon plasma by Mott dissociation of hadrons and compare results with data from lattice QCD simulations. We consider the thermodynamics of the Polyakov-loop extended Nambu–Jona-Lasinio (PNJL) model within the self consistent...
In this poster, we propose an approach for the Higgs boson as top-quark condensate within non-local Nambu–Jona-Lasinio (NJL) model. The advantage of non-local models over local ones is the spectrum of composed particle masses, which has a lower value than the sum of masses of particles of which it consists. By adjusting two parameters in the non-local NJL, the interaction range and the...
The QCD phase diagram and transitions between quark and hadron phases are in the focus of recent investigations in both theoretical and experimental fields of heavy energy physics. For a description of matter at high temperature and density effective models of Nambu-Jona-Lasinio-type have proven most useful. On the basis of NJL-type models it is possible to describe the chiral restoration...
A novel approach to identify the geometrical (anti)clusters formed by the Polyakov loops of the same sign and to study their properties in the lattice SU(2) gluodynamics is developed. The (anti)cluster size distributions are analyzed for the lattice coupling constant {$\beta =[2.3115; 3]$}. The found distributions are similar to the ones existing in 2- and 3-dimensional Ising systems [1]....
In this poster, we outline a two-phase description of the quark-nuclear matter hybrid equation of state that takes into account effects of phase space occupation (excluded volume) in both, the hadronic and the quark matter phases. For the nuclear matter phase, the reduction of the available volume at increasing density leads to a stiffening, while for the quark matter phase a reduction of the...
We study the combined effects of two and three-body local interactions as well as the finite temperature on the phase diagram of simple lattice bosons model. In order to handle system with strong local interactions we use the resolvent expansion technique, based on the contour integral representation of a partition function, and to find the phase diagram we derive Landau-type expansion for...
vHLLE solves the equations of relativistic viscous hydrodynamics in 3+1 dimensions using Israel-Stewart framework. In addition to energy and momentum, charge densities are explicitly propagated and included in the equation of state, making the code suitable for simulations of matter expansion with ?nite baryon density. With the help of ideal-viscous splitting, we keep the ability to solve the...
