691 research outputs found
Evolution of the concept of Quark Matter: the Ianus face of the heavy ion collisions
Since the beginning of the efforts to produce and understand quark matter
large changes developed in the ideas of description of this matter. In the
present paper we summarize some aspects of this development.Comment: Talk given at 18th International Conference on Ultrarelativistic
Nucleus-Nucleus Collisions: Quark Matter 2005 (QM 2005), Budapest, Hungary,
4-9 Aug 2005. 10 pages, 7 figure
K*(892)0 Production in Relativistic Heavy Ion Collisions at sqrt(s_NN) = 130 GeV
Preliminary results on the K*(892)0 -> pi + K production using the
mixed-event technique are presented. The measurements are performed at
mid-rapidity by the STAR detector in sqrt(s_NN) = 130 GeV Au-Au collisions at
RHIC. The K*0 to negative hadron, kaon and phi ratios are obtained and compared
to the measurements in e+e-, pp and pbarp at various energies.Comment: 8 pages, 3 figures, proceedings of Strange Quarks in Matter
(SQM2001), Frankfurt am Main, Germany, to be published in J. Phys.
Evidence for chemical equilibration at RHIC
This contribution focuses on the results of statistical model calculations at
RHIC energies, including recently available experimental data. Previous
calculations of particle yield ratios showed good agreement with measurements
at SPS and lower energies, suggesting that the composite system possesses a
high degree of chemical equilibrium at freeze-out. The effect of feeddown
contamination on the model parameters is discussed, and the sensitivity of
individual ratios to the model parameters (, ) is illustrated.Comment: Talk presented at Strange Quarks in Matter 2001, Frankfurt, September
24-29, 2001. Proceedings to be published by J. Phys. G. 8 pages with 4
figure
Resonance Production
Recent results on rho(770)^0, K(892)^*0, f_0(980), phi(1020), Delta(1232)^++,
and Lambda(1520) production in A+A and p+p collisions at SPS and RHIC energies
are presented. These resonances are measured via their hadronic decay channels
and used as a sensitive tool to examine the collision dynamics in the hadronic
medium through their decay and regeneration. The modification of resonance
mass, width, and shape due to phase space and dynamical effects are discussed.Comment: 8 pages, 10 figures, proceedings of the Quark Matter 2004, in
Oakland, California, to be published in Journal of Physics G: Nuclear and
Particle Physic
Strange Hadron Resonances and QGP Freeze-out
We describe how the abundance and distribution of hyperon resonances can be
used to probe freeze-out conditions. We demonstrate that resonance yields allow
us to measure the time scales of chemical and thermal freeze-outs. This should
permit a direct differentiation between the explosive sudden, and staged
adiabatic freeze-out scenarios.Comment: 8 pages including 4 figures, in Proceedings of Strange Quark Matter
2001, Frankfurt, submitted to J. Phys. G version 2: refernces
corrected/added, numercial corrections in figures 2,3,
Production in Au+Au and pp Collisions at = 200GeV at STAR
Mid-rapidity and are
measured in Au+Au and pp collisions at =200GeV using the STAR
detector at RHIC. The mass is systematically shifted at small
transverse momentum for both Au+Au and pp collisions. The
transverse mass spectra are measured in Au+Au collisions at different
centralities and in pp collisions. The mean transverse momentum
as a function of the collision centrality is compared to those of identified
, and . The and ratios are
compared to measurements in A+A, , , collisions at
various colliding energies. The physics implications of these measurements are
also discussed.Comment: 6 pages, 4 figures, proceedings of Strange Quarks in Matter
(SQM2003), Atlantic Beach, USA, to be published in J. Phys.
Recent results on strangeness production from NA49
We present a summary of measurements of strange particles performed by the
experiment NA49 in inelastic p+p interactions, as well as semi-central C+C and
Si+Si, central Pb+Pb, and minimum bias Pb+Pb collisions in the energy range
= 6.3 - 17.3 GeV. New results on , and
production in minimum bias Pb+Pb collisions at = 8.7 and 17.3
are shown. Furthermore the strangeness enhancement factor at =
17.3 GeV is presented and compared to the results from NA57 and STAR. Energy
dependence of strange particle yields normalized to pion yields is presented.
New data on production are shown at = 17.3
GeV. Furthermore we present the energy dependence of and
fluctuations. The data are compared with model predictions.Comment: 9 pages, 7 figures, Submitted to J. Phys. G (Proceedings of the
International Conference on Strangeness in Quark Matter, Buzios, Rio de
Janeiro, Brazil, September 27 - October 2, 2009
Dynamics and freeze-out of hadron resonances at RHIC
Yields, rapidity and transverse momentum spectra of ,
, and the meson resonances ,
, and are predicted. Hadronic rescattering leads to a
suppression of reconstructable resonances, especially at low . A mass
shift of the of 10 MeV is obtained from the microscopic simulation, due
to late stage formation in the cooling pion gas.Comment: Proceedings of the Strange Quark Matter 2003, eprint version differs
from published versio
Future Experiments in Relativistic Heavy Ion Collisions
The measurements at RHIC have revealed a new state of matter, which needs to
be further characterized in order to better understand its implications for the
early evolution of the universe and QCD. I will show that, in the near future,
complementary key measurements can be performed at RHIC, LHC, and FAIR. I will
focus on results than can be obtained using identified particles, a probe which
has been the basis for this conference over the past three decades. The
sophisticated detectors, built and planned, for all three accelerator
facilities enable us to measure leptons, photons, muons as well as hadrons and
resonances of all flavors almost equally well, which makes these experiments
unprecedented precision tools for the comprehensive understanding of the
physics of the early universe.Comment: 10 pages, 4 figures, Proceedings for Summary Talk at SQM 2007,
Levoca, Slovakia, June 24-29, 200
Production of resonances in a thermal model: invariant-mass spectra and balance functions
We present a calculation of the pi+ pi- invariant-mass correlations and the
pion balance functions in the single-freeze-out model. A satisfactory agreement
with the data for Au+Au collisions is found.Comment: Contribution to QM 2004 (4 pages, 2 figures
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