64 research outputs found
Particle dependence of elliptic flow in Au+Au collisions at 200 GeV
The elliptic flow parameter () for and
has been measured at mid-rapidity in Au + Au collisions at
GeV by the STAR collaboration. The values for both
and saturate at moderate , deviating
from the hydrodynamic behavior observed in the lower region. The
saturated values and the scales where the deviation begins are
particle dependent. The particle-type dependence of shows features
expected from the hadronization of a partonic ellipsoid by coalescence of
co-moving quarks. These results will be discussed in relation to the nuclear
modification factor () which has also been measured for and
by the STAR collaboration.Comment: 6 pages, 3 figures, Strange Quark Matter 2003 Conference (SQM 2003):
updated with 2 figures from original talk that did not appear in the journa
Traces of Thermalization at RHIC
I argue that measurements of Au+Au collisions at 20, 130 and 200 GeV of the
centrality dependence of the mean p_t together with p_t and net-charge
fluctuations reflect the approach to local thermal equilibrium.Comment: 4 pages, 4 eps figures, for proc. Quark Matter 2004, to be published
in J. Phys.
Overview of the Status and Strangeness Capabilities of STAR
STAR is a large acceptance spectrometer capable of precision measurements of
a wide variety of strange particles. We discuss the STAR detector, its
configuration during the first two years of RHIC operation, and its initial
performance for Au+Au collisions. The expected performance for strangeness
physics and initial data on strange particle reconstruction in Au+Au collisions
are presented.Comment: Proceedings of the Fifth International Conference on Strangeness in
Quark Matter, Berkeley, California, July 20-25, 200
Event-by-Event Fluctuations at 40, 80, and 158 AGeV/c in Pb+Au Collisions
Event-by-event fluctuations of mean pt and net charge in 40, 80, and 158
AGeV/c Pb+Au collisions are presented. The observed dynamical mean pt
fluctuations in central events of about 1 % are very similar to results from
RHIC. The centrality dependence of mean pt fluctuations at 158 AGeV/c shows a
peculiar non-monotonic pattern with respect to the extrapolation from the
fluctuations measured in p+p collisions. Dynamical net charge fluctuations
smaller than the charge conservation limit are observed. After correction for
charge conservation, the measured fluctuation signal in central events is
comparable to RHIC results.Comment: 4 pages, 6 figures, proceedings of the Quark Matter 2004, in Oakland,
USA, to be published in Journal of Physics G: Nuclear and Particle Physic
meson production in = 200 GeV Au+Au and pp collisions at RHIC
We present the results for the measurement of meson production in
= 200 GeV Au+Au and pp collisions at the Relativistic Heavy Ion
Collider (RHIC). Using the event mixing technique, spectra and yields are
obtained from the decay channel for different centrality
bins in Au+Au collisions and in pp collisions. We observe that the spectrum
shape in Au+Au collisions depends weakly on the centrality and the shape of the
spectrum in pp collisions is significantly different from that in Au+Au
collisions. In Au+Au collisions, the extracted yield of meson is flat as
a function of rapidity; The of , extracted from the fit function
to the spectra, shows a different behavior as a function of centrality than
that of , and Comment: Proceedings for the 7th International Conference on Strangeness in
Quark Matte
production and Cronin effect from p+p, d+Au and Au+Au collisions at GeV from the PHENIX experiment
We present results on identified particle production in p+p, d+Au and Au+Au
collisions at GeV at mid-rapidity measured by the PHENIX
experiment. The centrality and flavor dependence of the Cronin effect in d+Au
collisions is measured. The Cronin effect for the protons in d+Au is larger
than that for the pions, but not large enough to account for the ``anomalous''
proton to pion ratio in central Au+Au collisions.Comment: 5 pages, 3 figures, contribution to the proceedings of the 17th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2004
An Overview of Fluctuation and Correlation Results in Relativistic Heavy Ion Collisions
A great deal of recent data on event-by-event fluctuation and correlation
measurements has been released by several experiments at the SPS and RHIC.
Recent results on charge fluctuations, balance functions in pseudorapidity, and
average transverse momentum fluctuations will be reviewed. The results will be
compared to various model predictions after examining contributions to each
observable from known physics processes.Comment: 8 pages, 3 figures. Contribution to the Proceedings of the 17th
International Conference on Ultra Relativistic Nucleus-Nucleus Collisions
(Quark Matter 2004), Oakland, California, 11-17 Jan 2004. Submitted to
J.Phys.
Space-time analysis of reaction at RHIC
Space-time information about the Au-Au collisions produced at RHIC are key
tools to understand the evolution of the system and especially assess the
presence of collective behaviors. Using a parameterization of the system's
final state relying on collective expansion, we show that pion source radii can
be tied together with transverse mass spectra and elliptic flow within the same
framework. The consistency between these different measures provide a solid
ground to understand the characteristics of collective flow and especially the
possible peculiar behavior of particles such as Xi, Omega or phi. The validity
of the short time scales that are extracted from fits to the pion source size
is also addressed. The wealth of new data that will soon be available from
Au-Au collisions at sqrt{s_{NN}} = 200 GeV, will provide a stringet test of the
space-time analysis framework developped in these proceedings.Comment: Invited talk given at the SQM2003 conference (March 2003), to be
published in Journal of Physics G. 10 pages, 3 figure
RHIC Physics with the Parton Cascade Model
We present an analysis of the net-baryon number rapidity distribution and of
direct photon emission in the framework of the Parton Cascade Model.Comment: 4 pages 4 figures included, proceedings of QM 200
Open Charm Production at STAR
We present the open charm spectra at mid-rapidity from direct reconstruction
of D0, D* and D+/- in d+Au collisions at sqrt(sNN)=200 GeV using the STAR
detector at RHIC. The indirect electron/positron measurements via charm
semileptonic decays in p+p and d+Au collisions are also reported. The total
c\bar(c) cross section per nucleon-nucleon collision is extracted from both
direct and indirect measurements and are consistent with each other. By
combining the D0 and semileptonic measurements together, the cross section of
1.4+/-0.2+/-0.4 mb is higher than expectations from PYTHIA and other pQCD
calculations. The open charm pT distribution from direct measurements covers
the pT range up to ~10 GeV/c and follows a power-law distribution.Comment: 7 pages, 4 figures, proceedings for Hot Quark 04 Conference.
submitted to J. Phys. G: Nucl. Phy
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