OPUS 4 Latest Documents RSS FeedLatest documents
http://publikationen.ub.uni-frankfurt.de/index/index/
Mon, 23 Jan 2006 11:13:19 +0100Mon, 23 Jan 2006 11:13:19 +0100Hypermatter : properties and formation in relativistic nuclear collisions
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2994
The extension of the Periodic System into hitherto unexplored domains - anti- matter and hypermatter - is discussed. Starting from an analysis of hyperon and single hypernuclear properties we investigate the structure of multi-hyperon objects (MEMOs) using an extended relativistic meson field theory. These are contrasted with multi-strange quark states (strangelets). Their production mechanism is stud- ied for relativistic collisions of heavy ions from present day experiments at AGS and SPS to future opportunities at RHIC and LHC. It is pointed out that abso- lutely stable hypermatter is unlikely to be produced in heavy ion collisions. New attention should be focused on short lived metastable hyperclusters ( / 10 10s) and on intensity interferometry of multi-strange-baryon correlations.Lars Gerland; Christian Spieles; Marcus Bleicher; Panajotis Papazoglou; Jörg Brachmann; Adrian Dumitru; Horst Stöcker; Walter Greiner; Jürgen Schaffner; Carsten Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2994Mon, 23 Jan 2006 11:13:19 +0100Phase transition in the chiral sigma-omega model with dilatons
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3002
We investigate the properties of di erent modifications to the linear -model (including a dilaton field associated with broken scale invariance) at finite baryon density and nonzero temperature T. The explicit breaking of chiral symmetry and the way the vector meson mass is generated are significant for the appearance of a phase of nearly vanishing nucleon mass besides the solution describing normal nuclear matter. The elimination of the abnormal solution prohibits the onset of a chiral phase transition but allows to lower the compressibility to a reasonable range. The repulsive contributions from the vector mesons are responsible for the wide range of stability of the normal phase in the (µ, T)-plane. The abnormal solution becomes not only energet- ically preferable to the normal state at high temperature or density, but also mechanically stable due to the inclusion of dilatons. PACS number:12.39.FPanajotis Papazoglou; Jürgen Schaffner; Stefan Schramm; Detlef Zschiesche; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3002Thu, 19 Jan 2006 14:26:55 +0100Chiral Lagrangian for strange hadronic matter
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3039
A generalized Lagrangian for the description of hadronic matter based on the linear SU(3)L × SU(3)R -model is proposed. Besides the baryon octet, the spin-0 and spin-1 nonets, a gluon condensate associated with broken scale invariance is incorporated. The observed values for the vacuum masses of the baryons and mesons are reproduced. In mean-field approximation, vector and scalar interactions yield a saturating nuclear equation of state. We discuss the di culties and possibilities to construct a chiral invariant baryon-meson interaction that leads to a realistic equation of state. It is found that a coupling of the strange condensate to nucleons is needed to describe the hyperon potentials correctly. The effective baryon masses and the appearance of an abnormal phase of nearly massless nucleons at high densities are examined. A nonlinear realization of chiral symmetry is considered, to retain a Yukawa-type baryon-meson interaction and to establish a connection to the Walecka-model.Panajotis Papazoglou; Stefan Schramm; Jürgen Schaffner-Bielich; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3039Thu, 05 Jan 2006 09:34:39 +0100Hypermatter in chiral field theory
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3038
Abstract. A generalized Lagrangian for the description of hadronic matter based on the linear SU(3)L × SU(3)R -model is proposed. Besides the baryon octet, the spin-0 and spin-1 nonets, a gluon condensate associated with broken scale invariance is incorporated. The observed values for the vacuum masses of the baryons and mesons are reproduced. In mean-field approximation, vector and scalar interactions yield a saturating nuclear equation of state. Finite nuclei can be reasonably described, too. The condensates and the e ective baryon masses at finite baryon density and temperature are discussed.Panajotis Papazoglou; Detlef Zschiesche; Stefan Schramm; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3038Thu, 05 Jan 2006 09:33:08 +0100Nuclei in a chiral SU(3) model
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3099
Nuclei can be described satisfactorily in a nonlinear chiral SU(3)-framework, even with standard potentials of the linearmodel. The condensate value of the strange scalar meson is found to be important for the properties of nuclei even without adding hyperons. By neglecting terms which couple the strange to the nonstrange condensate one can reduce the model to a Walecka model structure embedded in SU(3). We discuss inherent problems with chiral SU(3) models regarding hyperon optical potentials.Panajotis Papazoglou; Detlef Zschiesche; Stefan Schramm; Jürgen Schaffner-Bielich; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3099Mon, 12 Dec 2005 10:29:16 +0100Kaon effective mass and energy from a novel chiral SU(3) symmetric Lagrangian
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3098
A new chiral SU(3) Lagrangian is proposed to describe the properties of kaons and antikaons in the nuclear medium, the ground state of dense matter and the kaon-nuclear interactions consistently. The saturation properties of nuclear matter are reproduced as well as the results of the Dirac-Brückner theory. After taking into account the coupling between the omega meson and the kaon, we obtain similar results for the e ective kaon and antikaon energies as calculated in the one-boson-exchange model while in our model the parameters of the kaon-nuclear interactions are constrained by the SU(3) chiral symmetry. PACS number(s): 14.40.Aq, 12.39.Fe, 21.30.FeGuangjun Mao; Panajotis Papazoglou; Stefan Hofmann; Stefan Schramm; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3098Mon, 12 Dec 2005 10:10:27 +0100Effective kaon energy from a novel chiral SU(3) model
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3113
A new chiral SU(3) Lagrangian is proposed to describe the properties of kaons and anti-kaons in the nuclear medium. The saturation properties of nuclear matter are reproduced as well as the results of the Dirac-Brückner theory. After introducing the coupling between the omega meson and the kaon, our results for e ective kaon and anti-kaon energy are quite similar as calculated in the one-boson-exchange model.Guangjun Mao; Panajotis Papazoglou; Stefan Hofmann; Stefan Schramm; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3113Thu, 08 Dec 2005 11:13:50 +0100Chiral model for dense, hot and strange hadronic matter
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3145
Introduction: Until now it is not possible to determine the equation of state (EOS) of hadronic matter from QCD. One succesfully applied alternative way to describe the hadronic world at high densities and temperatures are effective models like the RMF-models [1], where the relevant degrees of freedom are baryons and mesons instead of quarks and gluons. Since approximate chiral symmetry is an essential feature of QCD, it should be a useful concept for building and restricting e ective models. It has been shown [2,3] that effective sigma-omega models including SU(2) chiral symmetry are able to obtain a reasonable description of nuclear matter and finite nuclei. Recently [4] we have shown that an extended SU(3) × SU(3) chiral sigma-omega model is able to describe nuclear matter ground state properties, vacuum properties and finite nuclei satisfactorily. This model includes the lowest SU(3) multiplets of the baryons (octet and decuplet[5]), the spin-0 and the spin-1 mesons as the relevant degrees of freedom. Here we will discuss the predictions of this model for dense, hot, and strange hadronic matter.Detlef Zschiesche; Panajotis Papazoglou; Christian W. Beckmann; Stefan Schramm; Jürgen Schaffner-Bielich; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3145Tue, 29 Nov 2005 10:40:12 +0100Hadrons in dense resonance matter: a chiral SU(3) approach
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3184
A nonlinear chiral SU(3) approach including the spin 3 2 decuplet is developed to describe dense matter. The coupling constants of the baryon resonances to the scalar mesons are determined from the decuplet vacuum masses and SU(3) symmetry relations. Di erent methods of mass generation show significant differences in the properties of the spin- 3 2 particles and in the nuclear equation of stateDetlef Zschiesche; Panajotis Papazoglou; Stefan Schramm; Jürgen Schaffner-Bielich; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3184Wed, 23 Nov 2005 11:28:55 +0100Superheavy nuclei in a chiral hadronic model
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3182
Superheavy nuclei are investigated in a nonlinear chiral SU(3)-model. The proton number Z=120 and neutron numbers of N=172, 184 and 198 are predicted to be magic. The charge distributions and alpha-decay chains hint towards a hollow stucture.Christian Beckmann; Panajotis Papazoglou; Detlef Zschiesche; Stefan Schramm; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3182Wed, 23 Nov 2005 10:13:43 +0100Nuclei, superheavy nuclei, and hypermatter in a chiral SU(3) model
http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3259
A model based on chiral SU(3)-symmetry in nonlinear realisation is used for the investigation of nuclei, superheavy nuclei, hypernuclei and multistrange nuclear objects (so called MEMOs). The model works very well in the case of nuclei and hypernuclei with one Lambda-particle and rules out MEMOs. Basic observables which are known for nuclei and hypernuclei are reproduced satisfactorily. The model predicts Z=120 and N=172, 184 and 198 as the next shell closures in the region of superheavy nuclei. The calculations have been performed in self-consistent relativistic mean field approximation assuming spherical symmetry. The parameters were adapted to known nuclei.Christian Beckmann; Panajotis Papazoglou; Detlef Zschiesche; Stefan Schramm; Horst Stöcker; Walter Greinerpreprinthttp://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3259Thu, 17 Nov 2005 13:07:00 +0100