TALK CONTRIBUTIONS
Author:
Francesco Becattini (University of Florence & FIAS Frankfurt)
Title:
Chemical equilibrium and chemical freeze-out
Abstract:
I will present a reanalysis of hadron production in relativistic nuclear collisions in view of recent measurements of proton and antiproton multiplicities at SPS and LHC. The low values of such multiplicities with respect to statistical model predictions can be accounted for by inelastic rescattering after hadronization. This phenomenon implies a correction to the concept of equilibrium chemical freeze-out. Using corrections from transport models, such as UrQMD, it is possible to reconstruct the primordial hadronization conditions, which occur at chemical equilibrium and nicely overlap with lattice QCD extrapolations at finite µB.
NOTES:
1 Author:
Sanjin Benić (University of Zagreb)
Title:
Hybrid stars from lattice constrained non-local PNJL model
Abstract:
Existing lattice data on the QCD phase diagram in the finite chemical potential region suggests that a strong vector channel interaction is present between quarks in the medium. This leads to a dramatic change of the cold quark Equation of State, in the sense that quark matter always appears as a state of lower pressure for a range of modern nuclear Equations of State. We will present some results of an ongoing study to reconcile this peculiar property in favor of quark matter at high densities, as is required by the property of asymptotic freedom. This will allow us to build hybrid Equations of State and test the model against new observations of heavy neutron stars.
NOTES:
2 Author:
Georg Bergner (ITP University Frankfurt)
Title:
Finite temperature analysis with effective Polyakov loop actions derived from a strong coupling expansion
Abstract:
Effective Polyakov loop models are a useful tool for an investigation of pure Yang-Mills theory and full QCD. A systematic derivation of the effective action can be done in a strong coupling expansion. Quite accurate predictions for phase transition have been obtained with this approach. In a hopping parameter expansion this approach can be extended to full QCD, even at finite chemical potential. Besides the phase transition also other observables are accessible within the framework of these effective theories. As a further test of this approach the free energy of the static quark-antiquark pair in the effective theory is compared with the results in full Yang-Mills theory.
NOTES:
3 Author:
Marcus Bleicher (University of Frankfurt)
Title:
Hybrid modelling of heavy ion collisions
Abstract:
We present a review on the latest developments within the framework of coupled Boltzmann-hydrodynamics hybrid approaches to relativistic heavy ion collisions. We will start from global observables, and discuss initial state fluctuations, and heavy quark dy- namics. Then we will present potential technical and physical improvements to the present simulations.
NOTES:
4 Author:
Michael Buballa (TU Darmstadt)
Title:
Inhomogeneous chiral-symmetry breaking phases
Abstract:
I discuss inhomogenous chiral symmetry breaking, focusing on new developments since the XXVIII Max Born Symposium 2011 (see Acta Phys. Polon. Supp. 5 641 (2012)). This includes an improved treatment of vector interactions, two-dimensional modulations, and a study of chiral density waves with Dyson-Schwinger equations.
NOTES:
5 Author:
Margaret Carrington (Brandon University)
Title:
Renormalization group flow equations connected to the nPI effective action
Abstract:
I discuss two non-perturbative techniques, the nPI effective action and the exact renor- malization group. At lowest order, it is known that the renormalization group flow equa- tions can be truncated using using the 4-point Bethe-Salpeter vertex obtained from the 2PI effective action. I show that one can truncate at the level of the second renormaliza- tion group flow equation using a coupled pair of Bethe-Salpeter type integral equations obtained from the 4PI effective action. Furthermore, the resulting flow equations for the 2- and 4-point functions are total derivatives whose integrals give the 4PI eom’s. This result indicates that there is a direct connection between the two formalisms. There may be practical advantages in reformulating the nPI integral equations as flow equations, since solving initial value problems is usually easier than solving non-linear integral equations.
NOTES:
6 Author:
Jean Cleymans (University of Cape Town)
Title:
The Tsallis distribution at the LHC
Abstract:
The Tsallis distribution was introduced in 1988 by Constantin Tsallis and has been used in many fields of physics. It has been widely used in high energy physics by the large experimental collaborations (PHENIX, STAR, ALICE, ATLAS, CMS, ...) mainly to describe transverse momentum distributions. Despite this, it has not received much attention from the theoretical high energy physics community. In this talk we will present a short review of the Tsallis distribution focusing on the use in high energy physics. A proposal will be considered to bring consistency to the values of the Tsallis parameter q and the corresponding temperature T.
NOTES:
7 Author:
Katarzyna Deja (National Centre for Nuclear Research)
Title:
Parton’s energy loss in unstable plasmas
Abstract:
Quark-gluon plasma produced at the early stage of relativistic heavy-ion collisions is unstable due to anisotropic parton’s momentum distribution. We develop a formalism to compute an energy loss of a fast parton traversing the unstable plasma. A magnitude of the energy loss per unit length, which is obtained as a solution of initial value problem, is shown to exponentially grow in time.
References:
Parton Energy Loss in the Extremely Prolate Quark-Gluon Plasma, e-Print: arXiv:1301.4563 [hep-ph] Parton Energy Loss in an Unstable Quark-Gluon Plasma, published in: Acta Phys.Polon.Supp. 5 (2012) 947 Parton Energy Loss in Two-Stream Plasma System, published in: Acta Phys.Polon.Supp. 5 (2012) 343-348
NOTES:
8 Author:
Alexander Dubinin (JINR, Dubna)
Title:
Diquarks in the effective QCD
Abstract:
We consider diquarks in the effective QCD at finite temperature and density. Temper- ature dependence of the diquark masses are obtained. The results are compared with the existing calculations.
NOTES:
9 Author:
Tobias Fischer (GSI/TU Darmstadt)
Title:
Deconfinement phase transition to strange quark matter in core-collapse supernova simulations
Abstract:
Current heavy-ion collider facilities such as the LHC at CERN in Geneva (Switzerland), RHIC in Brookhaven (US), and RIKEN in Tokyo (Japan) are mainly devoted to probe the state of matter with respect to a possible signal from the de-confinement (phase) transition, where the possibly de-confined quarks recombine to form the bound-state baryons. They mainly explore high temperatures on the order of several 100 MeV and low densities, a state of matter at high entropy per baryon which represents the early universe. On the other hand, NICA in Dubna (Russia) and, still under construction, FAIR at the GSI in Darmstadt (Germany) may be able to access the possible de-confinement (phase) transition at high densities and temperatures on the order of several tens of MeV. It corresponds to a state of matter at low and intermediate entropy per baryon, which in astrophysics represents neutron-star matter as well as supernova matter. In addition, simulations of astronomical objects and astrophysical phenomena can be used as powerful laboratories to probe conditions that are inaccessible for the currently operating heavy-ion collider facilities. In this talk I review the latter aspect, starting with a brief introduction to core-collapse supernova phenomenology, I will then summarize the past and recent efforts to study the possible impact of the de-confinement (phase) transition on the supernova dynamics. Special emphasis will be given to extract possible observables, e.g., the neutrino signal from such event. I will also discuss current constraints from heavy-ion collision experiments and astrophysics. Both of which must be considered when constructing an equation of state valid for astrophysical applications, independent from the structures contained, e.g., baryons, de-confined quarks, or both.
NOTES:
10 Author:
Bengt Friman (GSI)
Title:
Fluctuations on the phase boundary
Abstract:
I explore the relevance of higher order cumulants of net baryon number fluctuations for the analysis of freeze-out and critical conditions in heavy ion collisions at LHC and RHIC. The generic structure of these higher cumulants at vanishing baryon chemical potential are related to the O(4) scaling functions. Chiral model calculations are used to explore their properties at non-zero baryon chemical potential. I argue that the higher order cumulants of baryon number and electric charge offer the possibility to probe the proximity of the thermal freeze-out to the crossover line.
NOTES:
11 Author:
Ernst-Michael Ilgenfritz (VBLHEP JINR, Dubna)
Title:
The thermal crossover with two flavors of twisted mass quarks
Abstract:
I will report about a finite-temperature study with two flavors of twisted mass Wilson fermions. This fermion formulation for lattice gauge theory simulations is not much used in this context, but it adds to the various types of fermions that need to be compared with respect to the phase structure. Results of the tmfT Collaboration concerning the thermal crossover for zero baryonic density (for a set of would-be pion masses) and their chiral extrapolation will be presented, as well as the status of the equation of state (EoS). Studies of the gluon propagator in Landau gauge have been extended to finite tem- perature, both in gluodynamics and to full QCD as represented by the tmfT simulations. Although the temperature dependence is not dramatic (even in the case of gluodynamics across the first order transition), the two cases can be related through Schwinger-Dyson equations with an appropriate quark mass.
NOTES:
12 Author:
Jakub Jankowski (University of Wrocław)
Title:
Chiral condensate and the structure of hadrons
Abstract:
A model of hadron masses based on quark structure of hadrons combined with effects of chiral dynamics is used to calculate 2+1 quark flavour chiral condensate in the hadron resonance gas framework. Results are discussed in the context of recent lattice QCD data. Extensions to the potential models of hadron structure will be discussed with the aim to estimate strange sigma term of the nucleon.
References:
J. Jankowski, D. Blaschke, M. Spaliński, ”Chiral condensate in hadronic matter”, Phys. Rev. D 87, 105018 (2013)
NOTES:
13 Author:
Burkhard Kämpfer (HZDR)
Title:
AdS/QCD: equation of state and viscosities
Abstract:
In a bottom-up approach, the gravity dual of the SU(3) gluon plasma is adjusted at recent lattice data. The viscosity coefficients follow then without further assumptions. The ratio of the bulk viscosity to entropy density shows an almost linear dependence on the non-conformality measure, as predicted also in a quasi-particle model. The ratio of shear viscosity to entropy density takes its KSS value irrespectively of the dilaton potential within a set-up with Hilbert action in the gravity part. The inclusion of quark degrees of freedom is discussed.
NOTES:
14 Author:
Frithjof Karsch (BNL and Universität Bielefeld)
Title:
Thermodynamics of strong interaction matter from lattice QCD and the hadron resonance gas model
Abstract:
The determination of the QCD crossover temperature from lattice QCD calculations at small values of the baryon chemical potential, on the one hand, and freeze-out temperatures obtained from experimentally determined particle yields through comparison with hadron resonance gas model calculations, on the other hand, suggest that freeze-out happens in the vicinity of the QCD transition. Although the hadron resonance gas model seemingly is very successful in describing freeze-out conditions it thus may be questionable whether this holds true for more infra-red sensitive observables like higher order charge fluctuations that are increasingly sensitive to critical behavior. We discuss generic properties of higher order cumulants of conserved charge fluctuations and compare lattice QCD results with hadron resonance gas model calculations as well as with experimental results on proton and electric charge fluctuations from the RHIC beam energy scan. We show that a direct comparison of the latter with QCD calculations allows a determination of freeze-out parameters and will allow an analysis of thermal conditions met at the time of freeze-out. We provide evidence for a break down of the hadron resonance gas model in the crossover region, which becomes more striking in thermal properties of fourth and sixth order cumulants.
NOTES:
15 Author:
Thomas Klähn (University of Wrocław)
Title:
Prospects for constraining the quark matter equation of state
Abstract:
We performed a full parameter scan regarding a subset of available interaction channels in the Nambu–Jona-Lasinio model for the dense, cold quark matter equation of state. Different regions in this parameter space are discussed highlighting the question whether quark matter in compact stars can be considered as a realistic scenario. This has direct implications for the investigation of the critical line in heavy ion collisions.
NOTES:
16 Author:
Che-Ming Ko (Texas A&M University)
Title:
Elliptic flow difference between particles and antiparticles and the EOS of baryon-rich matter
Abstract:
Using a relativistic transport model that includes both the partonic and hadronic phases, we show that the elliptic flow difference between particles and antiparticles in the baryon-rich matter produced in HIC is sensitive to both the partonic and hadronic mean fields, providing thus the possibility to study the EOS of QGP at finite baryon chemical potential.
NOTES:
17 Author:
Edwin Laermann (Universitaet Bielefeld)
Title:
Hadron correlators and restored symmetries at high temperature
Abstract:
In the vacuum the chiral symmetry of QCD is spontaneously broken. This is reflected in the appearance of pseudoscalar Goldstone particles and non-degenerate chiral partners. At high temperature chiral symmetry is restored in the chiral limit. While this should lead to identical spectral functions in the vector and axialvector channel, for 2 light flavors the situation in the scalar-pseudoscalar channel however depends on the effective restora- tion of the anomalous UA(1). In the talk, results from lattice QCD simulations for the corresponding hadronic correlators at non-vanishing temperature will be presented.
NOTES:
18 Author:
Ziwei Lin (East Carolina University)
Title:
Recent developments of a multi-phase transport model
Abstract:
After the public release of A Multi-Phase Transport (AMPT) model in 2004 and the detailed descriptions of its physics in Phys. Rev. C (2005), the AMPT model has been continuously updated and developed, sometimes at users’ requests, to make it more ver- satile and to include more physical processes. I will give an overview of the status and recent developments of the AMPT model, including ongoing work to fix the violation of charge conservation in the code. Possible directions for future work will also be discussed.
NOTES:
19 Author:
Pok Man Lo (GSI)
Title:
Polyakov loop susceptibilities in pure gauge system
Abstract:
We shall present the new lattice data on Polyakov loop susceptibilities in SU(3) pure gauge system. Like the Polyakov loops, the susceptibilities can serve as the order parameter for the spontaneous Z3 center symmetry breaking. In the context of Polyakov loop effective models, these susceptibilities are related to the curvatures of the potential. We shall discuss how the new data can be employed to constrain various Polyakov loop models.
NOTES:
20 Author:
Larry McLerran (BNL, RBRC, CCNU)
Title:
The CGC and LHC p-Pb
Abstract:
I will compare theoretical expectations for p-PB collisions at LHC to expectations of CGC and Glasma.
NOTES:
21 Author:
Cole Miller (University of Maryland)
Title:
Challenges in the measurements of neutron star radii
Abstract:
The recent discovery of neutron stars near two solar masses has placed strong con- straints on the properties of cold matter at a few times nuclear saturation density. Even tighter constraints would come from precise and accurate radius measurements, but cur- rent inferences are dominated by systematic errors. I will give a candid overview of current methods used to estimate neutron star radii and assess prospects for reliable radii from future electromagnetic and gravitational wave observations.
NOTES:
22 Author:
Stanisław Mrówczyński (Jan Kochanowski University, Kielce)
Title:
N = 4 super Yang-Mills plasma
Abstract:
Motivated by the AdS/CFT duality, we study the N = 4 super Yang-Mills plasma in the regime of weak coupling and compare it to the QCD plasma. Collective excitations and collisional processes are discussed. Since the Keldysh-Schwinger approach is used, the collective excitations in both equilibrium and non-equilibrium plasma are under con- sideration. The dispersion relations of gluon, fermion, and scalar fields are found in the Hard Loop Approximation and the corresponding effective action is given. The binary collisional processes, which occur at the lowest nontrivial order of the coupling constant, are reviewed and then the transport properties of the plasma are discussed.
NOTES:
23 Author:
Azwinndini Muronga (University of Johannesburg)
Title:
Relaxation and coupling coefficients in third order relativistic fluid dynamics
Abstract:
The study of non-equilibrium and transport phenomena in hot and dense QCD matter, and in astrophysics and cosmology involves the understanding of the transport coefficients such as conductivities, viscosities and diffusion. In combination with the relaxation and coupling coefficients, the resulting relaxation times and lengths govern the physics of many different scales and make the relativistic dissipative fluid dynamics applicable over a wide range of applications. Relativistic dissipative fluid dynamics may be represented as a field theory of of 14 fields of particle density (net conserved charge, e.g., net baryon number) - particle flux (e.g., baryon flux) and energy-momentum-stress. The field equations are based on the con- servation laws of net conserved charge and energy-momentum, and on a balance of fluxes. The resulting equations contains the conductivities, viscosities and diffusion coefficients as the unknown functions while all the other coefficients may be calculated from the equation of state. These other coefficients are the relaxation and the coupling coefficients. They will be discussed here up to third order relativistic fluid dynamics.
NOTES:
24 Author:
Carlos Peña (University of Wrocław)
Title:
Role of X(3872) in the statistical hadronization model
Abstract:
The statistical hadronization model has been used to predict the thermal J/ψ yield in a gas of hidden and open charm hadrons. Final multiplicity of J/ψ consists of the thermal contribution and decay. In such counting process the decay from exotic resonances like the X(3872) into J/ψ has not been taken in consideration yet. In this talk I want to discuss how much this resonance contributes.
NOTES:
25 Author:
Johann Rafelski (University of Arizona)
Title:
Universal hadronization condition
Abstract:
Despite a change by a factor of 45 in reaction energy comparing RHIC-62 and LHC- 2760, and a wide range of geometric collision centrality considered in these experiments, and the resulting dynamical range in particle production of many orders of magnitude, we find that the hadron yields can be described successfully allowing only for significant changes in volume dV/dy and to lesser degree strangeness saturation γs. We find that hadronization occurs at γq ' 1.6 and T ' 140 MeV. Evaluation of the intensive bulk phys- ical properties of the fireball as defined by produced particles, including those observed and predicted, shows universal hadronization property of pressure, energy density, entropy density in all reaction systems available for analysis.
REPORT Based on:
M. Petran et al: http://arxiv.org/abs/arXiv:1303.0913 http://arxiv.org/abs/arXiv:1303.2098
NOTES:
26 Author:
Krzysztof Redlich (University of Wrocław & GSI)
Title:
Probability distribution of conserved charges and chiral transition
Abstract:
We will discuss the influence of a phase transition on the probability distributions of conserved charges. The arguments will be done within the Landau theory and in the Quark-Meson model using the renormalization group approach. We will also discuss the STAR data on the probability distribution of a net-proton number in the context of a possible remnants of the O(4) scaling in heavy ion collisions.
NOTES:
27 Author:
Gerd Röpke (University of Rostock)
Title:
Modification of nuclear matter properties due to cluster formation
Abstract:
At low densities, nuclear matter can be treated as multi-component mixture of different clusters, the so-called nuclear statistical equilibrium. Within a Green function approach, a quasiparticle treatment including mean-field effects as well as Pauli blocking allows to include medium effects so that a unified description of nuclear matter is possible, including a cluster-virial expansion in the low density limit and relativistic mean-field approaches near the saturation density. Applications are given for stellar objects (supernova explosions), heavy ion collisions (phase diagram, symmetry energy), and nuclear structure (Hoyle-like states, alpha-like correlations at the surface of heavy nuclei). The experimental determination of freeze-out temperatures and densities from the yields of light elements emitted in heavy ion collisions is discussed. Results from differ- ent experimental approaches are compared with those of model calculations carried out with and without the inclusion of medium effects, which become of relevance for baryon densities above 5 × 10−4fm−3. A quantum statistical (QS) model incorporating medium effects is in good agreement with the experimentally derived results at higher densities. A densitometer based on medium modified chemical equilibrium constants is proposed.
References:
G. Ropke, Nucl. Phys. A 867, 66 (2011) S. Typel, G. Röpke, D. Blaschke, T. Klähn, H.H. Wolter, PRC 81, 015803 (2010) L. Qin et al., Phys. Rev. Lett. 108, 172701 (2012) Bo Zhou, Y. Funaki, H. Horiuchi, Zhongzhou Ren, G. Ropke, P. Schuck, A. Tohsaki, Chang Xu, and T. Yamada, arXiv:1304.1244 G. Ropke, S. Shlomo, A. Bonasera, J. B. Natowitz, S. J. Yennello, A. B. McIntosh, J. Mabiala, L. Qin, S. Kowalski, K. Hagel, M. Barbui, K. Schmidt, G. Giulani, H. Zheng, and S. Wuenschel, arXiv:1305.3942
NOTES:
28 Author:
Chihiro Sasaki (FIAS)
Title:
Yang-Mills thermodynamics: an effective theory approach
Abstract:
We show that the Polyakov-loop potential can be derived, using a field theoretical methods, directly from the SU(3) Yang-Mills theory. A class of the Polyakov-loop effective potentials used so far in literature appears as limiting cases of our potential. We deduce the correspondence of U(L) to the strong-coupling expansion, of which the relevant coefficients of the gluon energy distribution are specified solely by characters of the SU(3) group. At high temperatures the derived gluon potential exhibits the correct asymptotic be- havior, whereas at low temperatures, it disfavors gluons as appropriate dynamical degrees of freedom. In order to quantify the Yang-Mills thermodynamics in a confined phase, we propose a hybrid approach which matches the effective gluon potential to the one of glueballs constrained by the QCD trace anomaly in the context of dilaton fields. We also discuss the interplay between the chromomagnetic and chromoelectric gluon dynamics.
NOTES:
29 Author:
Helmut Satz (University of Bielefeld)
Title:
Calibrating the in-medium behavior of quarkonia
Abstract:
Quarkonium production has been considered as a tool to study the medium formed in high energy nuclear collisions, assuming that the formation of a hot and dense environment modifies the production pattern observed in elementary collisions. The basic features measured there are the relative fractions of hidden to open heavy flavor and the relative fractions of the different hidden heavy flavor states. Hence the essential question is if and how these quantities are modified in nuclear collisions. We show how the relevant data must be calibrated, i.e., what reference has to be used, in order to determine this in a model-independent way.
NOTES:
30 Author:
Bernd-Jochen Schaefer (University Giessen)
Title:
On Baryons and the QCD phase structure
Abstract:
Baryons play an important role for the QCD phase structure at increasing densities. Due to its complexity baryonic degrees of freedom are usually neglected in three color studies with functional methods. The proper inclusion of baryonic degrees of freedom is much simpler in a two-color world. In this talk we begin with a discussion of recent two- and three-flavor investigations of the QCD phase structure including the axial anomaly with the functional renormalization group. Afterwards the effects of baryonic degrees of freedom on the phase structure and equilibrium thermodynamics for two-color QCD is presented.
NOTES:
31 Author:
Abdel Nasser Tawfik (ECTP @ MTI U.)
Title:
Review on intensive and extensive quantities in HEC
Abstract:
We review theoretical and experimental estimations for various intensive and exten- sive quantities in high-energy collisions, including fluctuations and correlations of different charges and the collective properties. It is intend to find universal description in depen- dence on collision energy, size and configuration.
NOTES:
32 Author:
Wolfgang Unger (Goethe Universität Frankfurt)
Title:
The phase diagram of lattice QCD in the strong coupling limit and away from it
Abstract:
The strong coupling limit of staggered lattice QCD has been studied since decades, both via Monte Carlo and Mean field theory. In this model, the finite density sign problem is mild and the full phase diagram can be studied, even in the chiral limit. It is however desirable to understand the effect of a finite lattice coupling β on the phase diagram in the µB-T plane in order to see how it might be related to the phase diagram of continuum QCD. Here we discuss how to construct an effective theory for non-zero lattice coupling, valid to O(β), and present Monte Carlo results incorporating these corrections.
NOTES:
33 Author:
Hendrik van Hees (FIAS)
Title:
Dynamics of the chiral phase transition
Abstract:
One of the most interesting questions, addressed by investigating ultrarelativistic heavy- ion collisions at RHIC, LHC, and the future FAIR and NICA facilities, is the structure of the phase diagram of strongly interacting matter. At vanishing baryochemical potential Lattice QCD indicates a crossover transition from hadronic to deconfined, chirally sym- metric partonic matter (QGP) at a transition temperature of about 160 MeV. Various effective models predict a first-order phase transition at finite baryo chemical potential at lower temperatures, and the first-order transition line is expected to end in critical point of a 2nd-order phase transition. The location of this critical point and first-order transition line in the temperature-baryochemical-potential plane is not known from first principles. The difficulty in investigating this questionexperimentally with heavy-ion col- lisions, e.g., by measuring fluctuations of baryon number or electric charge, is that the produced medium is of finite spacial extent and of a finite lifetime of ∼10 fm/c. In this talk I address the questionin how far our expectations from equilibrium calculations have to be modified in view of this non-equilibrium situation of a dynamically developing sys- tem. Using a simple quark-meson linear-sigma model I’ll provide a progress report on first numerical invstigations in this direction, starting from a realization of the mean-field approximation, implementing elastic quark-scattering, coupling to an external heat-bath, etc.
NOTES:
34 Author:
Nu Xu (CCNU/LBNL)
Title:
Recent results from RHIC beam energy scan
Abstract:
High-energy nuclear collisions provide a unique opportunity for studying the QCD phase structure. At zero baryon chemical potential, LGT calculations predicted the new state of matter that has been observed in ultra-relativistic heavy ion collisions at RHIC and LHC. However, both theoretically and experimentally speaking, the location and the nature of the transition from the QGP state to hadronic state remains to be elusive. Starting 2010, RHIC lunched the beam energy scan program in the center of mass energy range of 7.7GeV to 39GeV. In this talk we will discuss the recent results from the first beam energy scan at RHIC and the implications on the QCD phase diagram.
NOTES:
35 POSTER SESSION
Sanjin Benić, D. Blaschke, G. A. Contrera, D. Horvatic
"Lorentz symmetry breaking effects in nonlocal PNJL models beyond the mean field"
The structure of the nonlocal PNJL (nl-PNJL) model is upgraded in order to allow for terms in the quark selfenergy which violate Lorentz invariance due to the presence of the medium. We examine the critical properties, the phase diagram as well as the Equation of State. Some aspects of the Mott effect for pions and sigma mesons are discussed for the first time explicitly within a nl-PNJL model. We find that, due to the strong residual interactions in the quark-antiquark plasma medium after chiral symmetry restoration, the pion and sigma meson widths tend to be smaller than in local PNJL models.
David Blaschke, Agnieszka Wergieluk, Daniel Zabłocki
"Generalized Beth-Uhlenbeck approach to mesons in quark matter"
An important first step in the program of hadronization of chiral quark models is the bosonization in meson and diquark channels. We present this procedure at finite temper- atures and chemical potentials for the SU(2) flavor case of the PNJL model focussing on the scalar/pseudoscalar meson channel. The thermodynamic potential is given the Beth- Uhlenbeck form which allows a detailed discussion of bound state dissociation in hot, dense matter (Mott effect) in terms of the in-medium scattering phase shift of two-particle cor- relations. It is shown for the case without meson-diquark mixing that the phase shift can be separated into a continuum and a resonance part. In the latter, the Mott transition manifests itself by a change of the phase shift by π in accordance with the Levinson the- orem, when a bound state transforms to a resonance in the scattering continuum. The question of a selfconsistent quasiparticle picture within the 2PI formalism is discussed.
References:
A. Wergieluk, D. Blaschke, Yu. L. Kalinovsky and A. Friesen, “Pion dissociation and Levin- son’s theorem in hot PNJL quark matter”, Dubna Report No. E2-2013-19; arXiv:1212.5245 [nucl-th] D. Blaschke, D. Zablocki, M. Buballa and G. Roepke, “Generalized Beth–Uhlenbeck ap- proach to mesons and diquarks in hot, dense quark matter”, arXiv:1305.3907 [hep-ph]
38 Alexsander Dubinin
"Diquarks in the SU(2) Nambu–Jona–Lasinio model and the Polyakov–Nambu–Jona–Lasinio model"
Diquarks at finite temperature and density are studied using a two-flavor, color SU(2) (P)NJL model.
David Miller
"Condensation and confinement"
We discuss the relationships between the processses of condensation and confinement for quarks (antiquarks) and gluons in matter with strong interactions on the theoretical basis of quantum chromodynamics (QCD).
Daniel Nowakowski, M. Buballa, S. Carignano
"Inhomogeneous chiral symmetry breaking phases in asymmetric matter"
Recently it was shown that beside homogeneous phases also inhomogeneous phases can be present in the phase diagram of effective models for strongly-interacting matter. We present some results of our study on inhomogeneous chiral symmetry breaking phases in the Nambu–Jona-Lasinio model for asymmetric matter. First, we generalize the existing formalism to allow for non-zero isospin chemical potential and analyze the influence of such an imbalance in the quark occupation numbers on the phase diagram. Next, inde- pendent modulations of up and down quarks are considered and the effects on the spatially varying order parameter of the chiral symmetry breaking phases are studied. Finally, we discuss possible extensions of our approach, as the addition of inhomogeneous charged pion condensation or color superconductivity to our model.
39 Gerd Röpke, S. Typel, D. Blaschke, T. Klähn, H.H. Wolter "Nuclear equation-of-state with cluster correlations and the symmetry energy" Symmetry energy in supernovae and neutron stars is an important ingredient to cal- culate their properties, but is unclear in nuclear systems until now. Aim of the work is to construct the EoS from very low to high density for use in Nuclear Structure, Heavy Ion Collisions, and Stellar Objects, including cluster correlations in the medium; use a combination of generalized Relativistic Mean Field (RMF) for the single particle fields, with a Quantum Statistical approach (QS) for the medium properties of the composite clusters; determine consequences for the symmetry energy.
References:
S. Typel, G. Röpke, D. Blaschke, T. Klähn, H.H. Wolter, PRC 81, 015803 (2010) J. Natowitz, G. Röpke, S. Typel, H. Wolter, et al., PRL 104, 202501 (2012)
40