Refine
Year of publication
Document Type
- Article (200)
- Preprint (155)
- Conference Proceeding (4)
- Report (1)
- Working Paper (1)
Has Fulltext
- yes (361)
Is part of the Bibliography
- no (361)
Keywords
- Kollisionen schwerer Ionen (40)
- heavy ion collisions (33)
- equation of state (11)
- Quark-Gluon-Plasma (10)
- Zustandsgleichung (9)
- quark-gluon plasma (9)
- Hadron (8)
- Quark Gluon Plasma (8)
- heavy ion collision (8)
- QGP (7)
- Quanten-Chromodynamik (7)
- UrQMD (7)
- quark (7)
- Energie (6)
- Meson (6)
- Quark (6)
- heavy-ion collisions (6)
- meson (6)
- quark gluon plasma (6)
- relativistic (6)
- QCD (5)
- Quantum Chromodynamic (5)
- collision (5)
- energy (5)
- nucleon (5)
- Dirac (4)
- Drell-Yan (4)
- Kollision (4)
- LHC (4)
- QMD (4)
- Quark Materie (4)
- RQMD (4)
- SPS (4)
- gluon (4)
- hadronic (4)
- hydrodynamisches Modell (4)
- nuclear reactions (4)
- quark matter (4)
- relativistic quantum molecular dynamics (4)
- schwere Ion Kollision (4)
- Bremsstrahlung (3)
- EOS (3)
- Materie (3)
- Molekulare Dynamik (3)
- Neutronenstern (3)
- Nukleon (3)
- Strahl (3)
- Ultrarelativistic Quantum Molecular Dynamics (3)
- Zustandsgleichungen (3)
- baryon (3)
- bremsstrahlung (3)
- hadronic matter (3)
- heavy ion colliders (3)
- hydrodynamical model (3)
- jet (3)
- neutron star (3)
- nuclei (3)
- relativistisch (3)
- schwere Ion-Kollision (3)
- Dilepton (2)
- Dirac-Brueckner theory (2)
- Dirac-Brückner Theorie (2)
- Gluon (2)
- Heavy ion collisions (2)
- Kaon (2)
- Kerne (2)
- Lagrangian (2)
- Nambu Jona-Lasinio Modell (2)
- Nambu Jona-Lasinio model (2)
- Nucleon (2)
- Partikelspektren (2)
- Pion (2)
- Plasma (2)
- Quanten Chromodynamik (2)
- Quantenchromodynamik (2)
- Quantum Chromodynamics (2)
- Quantum Molecular Dynamics (2)
- Quark gluon Plasma (2)
- Quark-Gluon Plasma (2)
- Teilchen (2)
- Temperatur (2)
- UrQMD Modell (2)
- Walecka model (2)
- antibaryon (2)
- bound state (2)
- degrees of freedom (2)
- dense matter (2)
- dichte Materie (2)
- dilepton (2)
- freeze out (2)
- hadron (2)
- hadronische Materie (2)
- hydrodynamic description (2)
- kaon (2)
- kinetic equation (2)
- kinetische Gleichung (2)
- matter (2)
- nuclear matter (2)
- nucleus-nucleus collisions (2)
- particle spectra (2)
- pion (2)
- plasma (2)
- quark-gluon-plasma (2)
- relativistische (2)
- schwere Ione (2)
- statistical coalescence model (2)
- statistisches Fusionsmodell (2)
- strange hadronic matter (2)
- temperature (2)
- ultrarelativistisch (2)
- ultrarelativistische (2)
- (QGP) (1)
- 13C(16O (1)
- 17O) (1)
- 20Ne + 238U (1)
- 232Th (1)
- 234-238U calculated B (E2) values (1)
- AGS (1)
- Abhängigkeit von der Dichte (1)
- Absorption (1)
- Anti-Kaon (1)
- Antikaon (1)
- Antinukleonen (1)
- Ar + Pb (800 MeV/nucleon) relativistic heavy-ion reactions (1)
- Ar+Ca (1)
- Ausfrieren (1)
- BEVALAC (1)
- Baryon Resonance (1)
- Baryon-Resonanz (1)
- Bjorken Modell (1)
- Bjorken model (1)
- Boltzmann-Uehling-Uhlenbeck (1)
- Boltzmann-Uehling-Uhlenbeck Gleichung (1)
- Boltzmann-Uehling-Uhlenbeck equation (1)
- Bose (1)
- Bose-simulated pion production (1)
- Charmonium Produktion (1)
- Charmonium production (1)
- Cluster distribution (1)
- Cluster integrals (1)
- Conservation Laws (1)
- Deuteron (1)
- Dichte (1)
- Dielectron (1)
- Dielektron (1)
- Distributed software development (1)
- Drell-Yan production (1)
- Drell-Yan ratio (1)
- Drell-Yan-Prozess (1)
- Dynamik (1)
- Dyson-Schwinger equation (1)
- E1ab=400 MeV/nucleon fluid dynamics (1)
- Elab=393 MeV/nucleon (1)
- Elementarteilchen (1)
- Elementary particle (1)
- Equation of state (1)
- Ereignisschwankungen (1)
- Erhaltungsgesetz (1)
- Event-by-event fluctuations (1)
- Freeze Out (1)
- Freeze out (1)
- Freiheitsgrad (1)
- Freiheitsgrade (1)
- Geometrical modelling (1)
- Geometrisches Modellieren (1)
- Gluon-Plasma (1)
- Hadron Gas Modell (1)
- Hadron Materie (1)
- Hadronenbeschleuniger (1)
- Hartree (1)
- Homogeneous nucleation (1)
- Hypermaterie (1)
- IQMD Modell (1)
- IQMD model (1)
- In-Medium Zerfall (1)
- J/psi Erhöhung (1)
- J/psi Unterdrückung (1)
- J/psi enhancement (1)
- J/psi mesons (1)
- J/psi suppression (1)
- J/psi yield (1)
- J/ϕ (1)
- K-Meson (1)
- Kaons (1)
- Kern-Kern Kollision (1)
- Kern-Kern Kollisionen (1)
- Kernkollision (1)
- Kernmaterie (1)
- Kollisionen des schweren Ions (1)
- Korrelation (1)
- Lagrangian . equation of state (1)
- Large Hadron Collider (1)
- Lepton (1)
- Local thermodynamical equilibrium (1)
- Lorentz (1)
- Lorentz contraction (1)
- MEMOs (1)
- Massenspektrum (1)
- Monte Carlo Modell (1)
- Monte Carlo model (1)
- Monte-Carlo model for relativistic heavy ion collisions (1)
- Nambu Jona Lasinio Modell (1)
- Nambu Jona Lasinio model (1)
- Nambu-Jona-Lasinio (1)
- Nambu-Jona-Lasinio Modell (1)
- Nambu-Jona-Lasinio model (1)
- Ne+U (1)
- Neutronensterne (1)
- Nichtgleichgewicht (1)
- Nichtumkehrbarkeit (1)
- Non-equilibrium effects (1)
- Nucleus–nucleus collisions (1)
- OMD (1)
- Objectoriented technology (1)
- Objektorientierte Technologie (1)
- Particle Spectra (1)
- Particle interactions (1)
- Partikel-Wechselwirkungen (1)
- Pb+Pb collisions (1)
- Phasenübergang (1)
- Photon (1)
- Pion Gas (1)
- Pion-Produktion (1)
- QCD medium (1)
- QCD plasma (1)
- QGP hadrons phase transition (1)
- QGP signals (1)
- QMC (1)
- QMD Modell (1)
- QMD model (1)
- QSM (1)
- Quanten Chromodynamic (1)
- Quanten-Molekular-Dynamic (1)
- Quanten-Molekular-Dynamik (1)
- Quanten-Molekulardynamik (1)
- Quantendynamik (1)
- Quantum (1)
- Quantum chromodynamics (1)
- Quark Antiquark (1)
- Quark-Sterne (1)
- Quarkonium (1)
- RHIC (1)
- Raum Zeit (1)
- Relativistic Heavy Ion Collider (1)
- Relativistic heavy-ion reactions (1)
- Relativistisch (1)
- Rho-Meson (1)
- SHM (1)
- SU (3) - Modell (1)
- SU (3) - Symmetrie (1)
- SU (3) Modell (1)
- SU(3) model (1)
- SU(3)-model (1)
- SU(3)-symmetry (1)
- Schwankung (1)
- Simulation (1)
- Skalarpotential (1)
- Software engineering (1)
- Softwaretechnik (1)
- Statistical model (1)
- Strangelets (1)
- Strangeness production (1)
- Super Proton Synchrotron (1)
- Teilchenbeschleuniger (1)
- Teilchenspektren (1)
- Teilchenverteilung (1)
- Transportmodell (1)
- URQMD (1)
- Ultra-relativistic Quantum Molecular Dynamic (1)
- Ultra-relativistic Quantum Molecular Dynamics model (1)
- Ultrarelativisitic Quantum Molecular Dynamics model (1)
- Ultrarelativisitisches (1)
- Ultrarelativistic Quantum Molecular Model (1)
- Ultrarelativistisches Quant Molekular Dynamik (1)
- Ultrarelativistisches Quant Molekulares Modell (1)
- UrQMD model (1)
- Van der Waals (1)
- Van der Waals model (1)
- Vektorpotential (1)
- Verbreitung (1)
- Vielkörperkorrelationen (1)
- Walecka Modell (1)
- Walecka-Modell (1)
- Walecka-model (1)
- Zeitabhängig (1)
- Zusammenstoß (1)
- absorption (1)
- angular distribution (1)
- anti-kaon (1)
- anti-nucleons (1)
- antikaon (1)
- asymmetric two-center shell model (1)
- begrenzte Kerne (1)
- bestimmte Zustände (1)
- binaryfission (1)
- bound states (1)
- broadening (1)
- calculated level diagrams (1)
- charm and bottom Produktion (1)
- charm and bottom production (1)
- chemical (1)
- chemical freezeout (1)
- chemisches Ausfrieren (1)
- chiral SU (3) (1)
- chiral SU(3) (1)
- chiral SU(3) model (1)
- cold baryon rich matter (1)
- cold quark matter (1)
- collective model (1)
- color current (1)
- coloured quark dynamic (1)
- compressible flow (1)
- conservation law (1)
- conservation laws (1)
- cross sections (1)
- deconfinement phase transition (1)
- dense (1)
- density and momentum dependence (1)
- deuteron (1)
- dileptons (1)
- directed flow (1)
- double differential cross sections (1)
- energie (1)
- finite nuclei (1)
- flow (1)
- flow of nucleons (1)
- fluid dynamics (1)
- fluid dynamics with thermal breakup (1)
- freezeout (1)
- gluon plasma (1)
- hadron hadron Kollision (1)
- hadron hadron collision (1)
- hadron matter (1)
- hadron yield (1)
- hadronic fluctuation (1)
- hadronic freeze-out (1)
- hard-core (1)
- heat conduction (1)
- heavy ion scattering (1)
- heavy ions (1)
- heiße Kernmaterie (1)
- heiße Pion Materie (1)
- heiße und dichte Kernmaterie (1)
- heiße und dichte Materie (1)
- high energie (1)
- hitze (1)
- hohe Energie (1)
- homogene Nukleation (1)
- hot (1)
- hot and dense matter (1)
- hot and dense nuclear matter (1)
- hot hypernuclear matter (1)
- hot pion matter (1)
- hydrodynami (1)
- hydrodynamic model (1)
- hypermatter (1)
- hyperon (1)
- hyperonic Materie (1)
- hyperonic matter (1)
- ideal gas (1)
- ideales Gas (1)
- in-medium decay (1)
- in-medium properties (1)
- integro-differential equation (1)
- irreversibility state (1)
- kalte dunkle Materie (1)
- kaons (1)
- kinetic energy (1)
- kinetisches Ausfrieren (1)
- kinetisches Modell (1)
- kollidieren (1)
- lange hadron collider (1)
- lepton (1)
- lokales thermodynamisches Gleichgewicht (1)
- many-body correlations (1)
- mass spectra (1)
- meson mass (1)
- microscopic model (1)
- microscopic transport theory (1)
- mikroskopische Transporttheorie (1)
- mikroskopisches Modell (1)
- molecular theory of nucleon transfer (1)
- multicluster fission (1)
- neutron stars (1)
- niobium (1)
- non-equilibrium quantum field dynamics (1)
- nuclear (1)
- nuclear cold fission (1)
- nuclear collisions (1)
- nuclear hydrodynamics (1)
- nuclear shadowing (1)
- nuclear system (1)
- nucleon and nuclear cross sections (1)
- nucleon spectra (1)
- nuclera reactions (1)
- offene charm Produktion (1)
- open and hidden charm (1)
- open and hidden charm production (1)
- open charm production (1)
- open charm yield (1)
- pQCD (1)
- particle collisions (1)
- particle distribution (1)
- particle ratios (1)
- particles (1)
- partonic (1)
- perturbative Quantum Chromodynamic (1)
- photon (1)
- pion gas (1)
- quantum chromodynamic (1)
- quantum molecular dynamic (1)
- quantum molecular dynamics model (1)
- quantum statistical model (1)
- quark antiquark (1)
- quark gluon Plasma (1)
- quark shadowing (1)
- quark-meson coupling model (1)
- quarkonium (1)
- reich (1)
- relativistic heavy ion collider (1)
- relativistic heavy ion collision (1)
- relativistic heavy ion reactions (1)
- relativistic heavy-ion reactions (1)
- relativistic transport model (1)
- relativistische schwere Ion Kollision (1)
- relativistischer Schwerionen-Zusammenstoßer (1)
- rho meson (1)
- rich (1)
- saddle point shapes (1)
- scalar potential (1)
- schwere Ion-Kollisionen (1)
- schwere Ionen Kollision (1)
- second cluster integral (1)
- space-momentum correlation (1)
- space-time (1)
- statistical model (1)
- statistisches Modell (1)
- strange (1)
- strange quark star (1)
- strangelets (1)
- strangeness (1)
- superheavy (1)
- superheavy nuclei (1)
- superschwer (1)
- superschwere Kerne (1)
- system (1)
- thermal (1)
- thermalization (1)
- time dependent (1)
- true ternary fission (1)
- two-proton correlations (1)
- ultra-relativistic heavy ion collision (1)
- ultrarelativistic (1)
- ultrarelativistic energie (1)
- ultrarelativistic heavy-ion collision (1)
- ultrarelativistische Kollision des schweren Ionen (1)
- ultrarelativistische energie (1)
- van der Waals (1)
- vector mesons (1)
- vector potential (1)
- viscosity (1)
- zweite Gruppenintegral (1)
Institute
Equation of state of baryon rich quark matter is studied within the SU(3) Nambu Jona-Lasinio model with flavour mixing interaction. Possible bound states (strangelets) and chiral phase transitions in this matter are investigated at various values of strangeness fraction rs. The model predictions are very sensitive to the ratio of vector and scalar coupling constants, ¾ = GV /GS. At ¾ = 0.5 and zero temperature the maximum binding energy (about 15 MeV per baryon) takes place at rs C 0.4. Such strangelets are negatively charged and have typical life times < 10 7 s. The calculations are carried out also at finite temperatures. They show that bound states exist up to temperatures of about 15 MeV. The model predicts a first order chiral phase transition at finite baryon densities. The parameters of this phase transition are calculated as a function of rs.
We investigate the properties of charge neutral equilibrium cold quark matter within the Nambu Jona-Lasinio model. The calculations are carried out for di erent ratios of coupling constants characterizing the vector and scalar 4 fermion interaction, xi = GV /GS. It is shown that for xi < 0.4 matter is self bound and for xi < 0.65 it has a first order phase transition of the liquid gas type. The Gibbs conditions in the mixed phase are applied for the case of two chemical potentials associated with the baryon number and electric charge. The characteristics of the quark stars are calculated for xi = 0, 0.5 and 1. It is found that the phase transition leads to a strong density variation at the surface of these stars. For xi = 1 the properties of quark stars show behaviors typical for neutron stars. At >< 0.4 the stars near to the maximum mass have a large admixture of strange quarks in their interiors. PACS number: 14.65.-q, 26.60.+c, 97.10.-q
Irreversibility, steady state, and nonequilibrium physics in relativistic heavy ion collisions
(1999)
Heavy ion collisions at ultrarelativistic energies offer the opportunity to study the irreversibility of multiparticle processes. Together with the many-body decays of resonances, the multiparticle processes cause the system to evolve according to Prigogine s steady states rather than towards statistical equilibrium. These results are general and can be easily checked by any microscopic string-, transport-, or cascade model for heavy ion collisions. The absence of pure equilibrium states sheds light on the di culties of thermal models in describing the yields and spectra of hadrons, especially mesons, in heavy ion collisions at bombarding energies above 10 GeV/nucleon. PACS numbers: 25.75.-q, 05.70.Ln, 24.10.Lx
The ultrarelativistic quantum molecular dynamics model (UrQMD) is used to study global observables in central reactions of Au+Au at sqrt[s]=200A GeV at the Relativistic Heavy Ion Collider (RHIC). Strong stopping governed by massive particle production is predicted if secondary interactions are taken into account. The underlying string dynamics and the early hadronic decoupling implies only small transverse expansion rates. However, rescattering with mesons is found to act as a source of pressure leading to additional flow of baryons and kaons, while cooling down pions.
The equilibration of hot and dense nuclear matter produced in the central cell of central Au+Au collisions at RHIC (sqrt s = 200 A GeV) energies is studied within a microscopic transport model. The pressure in the cell becomes isotropic at t approx 5 fm/c after beginning of the collision. Within the next 15 fm/c the expansion of matter in the cell proceeds almost isentropically with the entropy per baryon ratio S/A approx 150, and the equation of state in the (P,epsilon) plane has a very simple form, P=0.15 epsilon. Comparison with the statistical model of an ideal hadron gas indicates that the time t approx 20 fm/c may be too short to reach the fully equilibrated state. Particularly, the creation of long-lived resonance-rich matter in the cell decelerates the relaxation to chemical equilibrium. This resonance-abundant state can be detected experimentally after the thermal freeze-out of particles.
The centrality dependence of (multi-)strange hadron abundances is studied for Pb(158 AGeV)Pb reactions and compared to p(158 GeV)Pb collisions. The microscopic transport model UrQMD is used for this analysis. The predicted Lambda/pi-, Xi-/pi- and Omega-/pi- ratios are enhanced due to rescattering in central Pb-Pb collisions as compared to peripheral Pb-Pb or p-Pb collisions. A reduction of the constituent quark masses to the current quark masses m_s \sim 230 MeV, m_q \sim 10 MeV, as motivated by chiral symmetry restoration, enhances the hyperon yields to the experimentally observed high values. Similar results are obtained by an ad hoc overall increase of the color electric field strength (effective string tension of kappa=3 GeV/fm). The enhancement depends strongly on the kinematical cuts. The maximum enhancement is predicted around midrapidity. For Lambda's, strangeness suppression is predicted at projectile/target rapidity. For Omega's, the predicted enhancement can be as large as one order of magnitude. Comparisons of Pb-Pb data to proton induced asymmetric (p-A) collisions are hampered due to the predicted strong asymmetry in the various rapidity distributions of the different (strange) particle species. In p-Pb collisions, strangeness is locally (in rapidity) not conserved. The present comparison to the data of the WA97 and NA49 collaborations clearly supports the suggestion that conventional (free) hadronic scenarios are unable to describe the observed high (anti-)hyperon yields in central collisions. The doubling of the strangeness to nonstrange suppression factor, gamma_s \approx 0.65, might be interpreted as a signal of a phase of nearly massless particles.
The equilibration of hot and dense nuclear matter produced in the central region in central Au+Au collisions at square root s = 200A GeV is studied within the microscopic transport model UrQMD. The pressure here becomes isotropic at t approx 5 fm/c. Within the next 15 fm/c the expansion of the matter proceeds almost isentropically with the entropy per baryon ratio S/A approx 150. During this period the equation of state in the (P, epsilon)-plane has a very simple form, P = 0.15 epsilon. Comparison with the statistical model (SM) of an ideal hadron gas reveals that the time of approx 20 fm/c may be too short to attain the fully equilibrated state. Particularly, the fractions of resonances are overpopulated in contrast to the SM values. The creation of such a long-lived resonance-rich state slows down the relaxation to chemical equilibrium and can be detected experimentally.
The relaxation of hot nuclear matter to an equilibrated state in the central zone of heavy-ion collisions at energies from AGS to RHIC is studied within the microscopic UrQMD model. It is found that the system reaches the (quasi)equilibrium stage for the period of 10-15 fm/c. Within this time the matter in the cell expands nearly isentropically with the entropy to baryon ratio S/A = 150 - 170. Thermodynamic characteristics of the system at AGS and at SPS energies at the endpoints of this stage are very close to the parameters of chemical and thermal freeze-out extracted from the thermal fit to experimental data. Predictions are made for the full RHIC energy square root s = 200$ AGeV. The formation of a resonance-rich state at RHIC energies is discussed.
Homogeneous nucleation of quark gluon plasma, finite size effects and longlived metastable objects
(1998)
The general formalism of homogeneous nucleation theory is applied to study the hadronization pattern of the ultra-relativistic quark-gluon plasma (QGP) undergoing a first order phase transition. A coalescence model is proposed to describe the evolution dynamics of hadronic clusters produced in the nucle- ation process. The size distribution of the nucleated clusters is important for the description of the plasma conversion. The model is most sensitive to the initial conditions of the QGP thermalization, time evolution of the energy den- sity, and the interfacial energy of the plasma hadronic matter interface. The rapidly expanding QGP is first supercooled by about T = T Tc = 4 6%. Then it reheats again up to the critical temperature Tc. Finally it breaks up into hadronic clusters and small droplets of plasma. This fast dynamics occurs within the first 5 10 fm/c. The finite size e ects and fluctuations near the critical temperature are studied. It is shown that a drop of longitudinally expanding QGP of the transverse radius below 4.5 fm can display a long-lived metastability. However, both in the rapid and in the delayed hadronization scenario, the bulk pion yield is emitted by sources as large as 3 4.5 fm. This may be detected experimentally both by a HBT interferometry signal and by the analysis of the rapidity distributions of particles in narrow pT -intervals at small |pT | on an event-by-event basis. PACS numbers: 12.38.Mh, 24.10.Pa, 25.75.-q, 64.60.Qb
We introduce a transport approach which combines partonic and hadronic degrees of freedom on an equal footing and discuss the resulting reaction dynamics. The initial parton dynamics is modeled in the framework of the parton cascade model, hadronization is performed via a cluster hadronization model and configuration space coalescence, and the hadronic phase is described by a microscopic hadronic transport approach. The resulting reaction dynamics indicates a strong influence of hadronic rescattering on the space-time pattern of hadronic freeze-out and on the shape of transverse mass spectra. Freeze-out times and transverse radii increase by factors of 2 3 depending on the hadron species.