204 research outputs found
Resonance Absorption and Regeneration in Relativistic Heavy Ion Collisions
The regeneration of hadronic resonances is discussed for heavy ion collisions
at SPS and SIS-300 energies. The time evolutions of Delta, rho and phi
resonances are investigated. Special emphasize is put on resonance regeneration
after chemical freeze-out. The emission time spectra of experimentally
detectable resonances are explored.Comment: Proceedings of the Nuclear Physics Winter Meeting 2005 in Bormi
Reconstructing and mesons from non-leptonic decays in C+C at 2AGeV
We predict transverse and longitudinal momentum spectra and yields of
and mesons reconstructed from hadron correlations in C+C
reactions at 2~AGeV. The rapidity and distributions for reconstructable
mesons differs strongly from the primary distribution, while the
's distributions are only weakly modified. We discuss the temporal and
spatial distributions of the particles emitted in the hadron channel. Finally,
we report on the mass shift of the due to its coupling to the
, which is observable in both the di-lepton and channel.
Our calculations can be tested with the Hades experiment at GSI, Darmstadt
Why the meson might be a difficult messenger for the restoration of chiral symmetry
We perform a theoretical analysis of the resonance mass spectrum in
ultra-relativistic heavy ion collisions within a hadron/string transport
approach. Predictions for the yield and its mass distribution are given
for the GSI-FAIR and the critRHIC energy regime. The potential of the
meson as a signal for chiral symmetry restoration is explored. In view of the
latest discussion, we investigate the decay channel in
detail and find a strong bias towards low masses. This apparent mass
shift of the if observed in the channel might render a
possible mass shift due to chiral symmetry restoration very difficult to
disentangle from the decay kinematics.Comment: 4 pages, 5 figure
Theoretical Analysis of Dilepton Spectra in Heavy Ion Collisions at GSI-FAIR Energies
This paper addresses the theoretical analysis of dilepton spectra in C+C
collisions at GSI-SIS energies. Theoretical predictions for the recent data of
the HADES collaboration at SIS-energies are made with the help of a
hadron-string transport model, the Ultra-relativistic Quantum Molecular
Dynamics (UrQMD) model. A mass shift of the meson due to kinematical
effects is discussed
Photon Signals from Quarkyonic Matter
We calculate the Bremsstrahlung photon spectrum emitted from dynamically
evolving quarkyonic matter, and compare this spectrum with that of a high
chemical potential quark-gluon plasma as well as to a hadron gas. We find that
the transverse momentum distribution and the harmonic coefficient is markedly
different in the three cases. The transverse momentum distribution of
quarkyonic matter can be fit with an exponential, but is markedly steeper than
the distribution expected for the quark-gluon plasma or a hadron gas, even at
the lower temperatures expected in the critical point region. The quarkyonic
elliptic flow coefficient fluctuates randomly from event to event, and within
the same event at different transverse momenta. The latter effect, which can be
explained by the shape of quark wavefunctions within quarkyonic matter, might
be considered as a quarkyonic matter signature, provided initial temperature is
low enough that the quarkyonic regime dominates over deconfinement effects, and
the reaction-plane flow can be separated from the fluctuating component.Comment: Accepted for publication, Phys.Rev.Lett. Discussion improved and
clarified, main conclusions unchange
Canonical suppression in microscopic transport models
We demonstrate the occurrence of canonical suppression associated with the conservation of an U(1)-charge in current transport models. For this study a pion gas is simulated within two different transport approaches by incorporating inelastic and volume-limited collisions pi pi leftrightarrow K bar-K for the production of kaon pairs. Both descriptions can dynamically account for the suppression in the yields of rare strange particles in a limited box, being in full accordance with a canonical statistical description
Dynamic canonical suppression of strangeness in transport models
It is investigated whether canonical suppression associated with the exact conservation of an U(1)-charge can be reproduced correctly by current transport models. Therefore a pion-gas having a volume-limited cross section for kaon production and annihilation is simulated within two different transport prescriptions for realizing the inelastic collisions. It is found that both models can indeed dynamically account for the canonical suppression in the yields of rare strange particles
Dileptonen und Resonanzen als Möglichkeit die heiĂe und dichte Phase nuklearer Materie zu erforschen
The thesis describes the possibilites to explore the hot and dense phase in heavy ion collisions. Therefore hadronic and leptonic decays of resonances are investigated.Die vorliegende Arbeit beschĂ€ftigt sich mit der Analyse von Signalen, die die hochdichte und heisse Phase einer Schwerionenkollision zu untersuchen. HierfĂŒr werden hadronische und leptonische ZerfallskanĂ€le von Resonanzen untersucht
The influence of bulk evolution models on heavy-quark phenomenology
We study the impact of different Quark-Gluon Plasma expansion scenarios in
heavy-ion collisions on spectra and elliptic flow of heavy quarks. For
identical heavy-quark transport coefficients relativistic Langevin simulations
with different expansion scenarios can lead to appreciable variations in the
calculated suppression and elliptic flow of the heavy-quark spectra, by up to a
factor of two. A cross comparison with two sets of transport coefficients
supports these findings, illustrating the importance of realistic expansion
models for quantitative evaluations of heavy-quark observables in heavy-ion
collisions. It also turns out that differences in freeze-out prescriptions and
Langevin realizations play a significant role in these variations. Light-quark
observables are essential in reducing the uncertainties associated with the
bulk-matter evolution, even though uncertainties due to the freeze-out
prescription persist.Comment: submitted to Physical Review
Hyperboloidal data and evolution
We discuss the hyperboloidal evolution problem in general relativity from a
numerical perspective, and present some new results. Families of initial data
which are the hyperboloidal analogue of Brill waves are constructed
numerically, and a systematic search for apparent horizons is performed.
Schwarzschild-Kruskal spacetime is discussed as a first application of
Friedrich's general conformal field equations in spherical symmetry, and the
Maxwell equations are discussed on a nontrivial background as a toy model for
continuum instabilities.Comment: 11 pages, 9 figures. To appear in the Proceedings of the Spanish
Relativity Meeting (ERE 2005), Oviedo, Spain, 6-10 Sept 200
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