578 research outputs found
Hadron production in relativistic nuclear collisions: thermal hadron source or hadronizing quark-gluon plasma?
Measured hadron yields from relativistic nuclear collisions can be equally
well understood in two physically distinct models, namely a static thermal
hadronic source vs.~a time-dependent, nonequilibrium hadronization off a
quark-gluon plasma droplet. Due to the time-dependent particle evaporation off
the hadronic surface in the latter approach the hadron ratios change (by
factors of ) in time. Final particle yields reflect time averages
over the actual thermodynamic properties of the system at a certain stage of
the evolution. Calculated hadron, strangelet and (anti-)cluster yields as well
as freeze-out times are presented for different systems. Due to strangeness
distillation the system moves rapidly out of the T, plane into the
-sector. Strangeness to baryon ratios f_s=1-2 prevail during a
considerable fraction (50%) of the time evolution (i.e. -droplets or
even -droplets form the system at the late stage: The possibility of
observing this time evolution via HBT correlations is discussed). The observed
hadron ratios require and . If
the present model is fit to the extrapolated hadron yields, metastable
hypermatter can only be produced with a probability for .Comment: Submitted to Z. Phys.
Parity Doublet Model applied to Neutron Stars
The Parity doublet model containing the SU(2) multiplets including the
baryons identified as the chiral partners of the nucleons is applied for
neutron star matter. The chiral restoration is analyzed and the maximum mass of
the star is calculated.Comment: Proceeding to the conference International Symposium on Exotic States
of Nuclear Matte
In-medium properties of D-mesons at FAIR
We obtain the D-meson spectral density at finite temperature for the
conditions of density and temperature expected at FAIR. We perform a
self-consistent coupled-channel calculation taking, as a bare interaction, a
separable potential model. The (2593) resonance is generated
dynamically. We observe that the D-meson spectral density develops a sizeable
width while the quasiparticle peak stays close to the free position. The
consequences for the D-meson production at FAIR are discussed.Comment: 4 pages, 3 figures, to appear in the proceedings of 9th International
Conference on Hypernuclear and Strange Particle Physics (HYP2006), Mainz
(Germany), 10-14 October 200
New Physics at the International Facility for Antiproton and Ion Research (FAIR) Next to GSI
The project of the international Facility for Antiproton and Ion Research
(FAIR), co-located to the GSI facility in Darmstadt, has been officially
started on November 7, 2007. The current plans of the facility and the planned
research program will be described. An investment of about 1 billion euro will
permit new physics programs in the areas of low and medium energy antiproton
research, heavy ion physics complementary to LHC, as well as in nuclear
structure and astrophysics. The facility will comprise about a dozen
accelerators and storage rings, which will enable simultaneous operations of up
to four different beams.Comment: 7 pages, 1 figure. Invited Talk presented at the "Fourth
International Conference on Fission and Properties of Neutron-Rich nuclei",
held at Sanibel Island, Florida, November 11-17, 200
Impact of baryon resonances on the chiral phase transition at finite temperature and density
We study the phase diagram of a generalized chiral SU(3)-flavor model in
mean-field approximation. In particular, the influence of the baryon
resonances, and their couplings to the scalar and vector fields, on the
characteristics of the chiral phase transition as a function of temperature and
baryon-chemical potential is investigated. Present and future finite-density
lattice calculations might constrain the couplings of the fields to the
baryons. The results are compared to recent lattice QCD calculations and it is
shown that it is non-trivial to obtain, simultaneously, stable cold nuclear
matter.Comment: 18 pages, 7 figure
Re-visit the N/Z ratio of free nucleons from collisions of neutron -rich nuclei as a probe of EoS of asymmetric nuclear matter
The N/Z ratio of free nucleons from collisions of neutron-rich nuclei as a
function of their momentum is studied by means of Isospin dependent Quantum
Molecular Dynamics.
We find that this ratio is not only sensitive to the form of the density
dependence of the symmetry potential energy but also its strength determined by
the symmetry energy coefficient.
The uncertainties about the symmetry energy coefficient influence the
accuracy of probing the density dependence of the symmetry energy by means of
the N/Z ratio of free nucleons of neutron-rich nuclei.Comment: 15 pages, 6 figures, 2 tables. accepted by Commun. Theor. Phys.
(Beijing, China
Collective flow of open and hidden charm in Au+Au collisions at = 200 GeV
We study the collective flow of open charm mesons and charmonia in Au+Au
collisions at = 200 GeV within the hadron-string-dynamics (HSD)
transport approach. The detailed studies show that the coupling of
mesons to the light hadrons leads to comparable directed and elliptic flow as
for the light mesons. This also holds approximately for mesons since
more than 50% of the final charmonia for central and mid-central collisions
stem from induced reactions in the transport calculations. The
transverse momentum spectra of mesons and 's are only very
moderately changed by the (pre-)hadronic interactions in HSD which can be
traced back to the collective flow generated by elastic interactions with the
light hadrons.Comment: 9 pages, 8 figures, Phys. Rev. C, in pres
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