552 research outputs found
Resonance Studies at STAR
We report on the observed signals of and
using the mixed-event method with powerful
statistics from the large acceptance and highly efficient STAR TPC. Preliminary
results from the first observation of such states from the year-one STAR data
in GeV Au-Au collisions are presented. The
ratios with an assumed inverse slope of
300MeV are compatible with that from pp at ISR. For 14% central Au+Au
collisions, we observe and
. We show that
from this method is consistent with
the measurement via decay topology.Comment: 4 pages, 4 figures, Quark Matter 2001, contributed talk; typos of
K*/h- numbers in abstract fixe
Antinucleus Production at RHIC
Light antinuclei may be formed in relativistic heavy ion collisions via final
state coalescence of antinucleons. The yields of antinuclei are sensitive to
primordial antinucleon production, the volume of the system at kinetic
freeze-out, and space-momentum correlations among antinucleons at freeze-out.
We report here preliminary STAR results on antideuteron and antihelion
production in 130A GeV Au+Au collisions. These results are examined in a
coalescence framework to elucidate the space-time structure of the antinucleon
source.Comment: 4 pages, 3 figures, talk given at Quark Matter 200
Spin physics with STAR
The STAR collaboration aims to study polarized proton-proton collisions at
RHIC. The emphasis of the spin run this year is on transverse single spin
asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon
polarization, as well as the polarizations of the u, , d and
quarks in the proton by measuring in addition longitudinal and double spin
asymmetries. Furthermore, we aim to measure for the first time the quark
transversity distributions. These measurements will improve substantially the
knowledge and understanding of the spin structure of the nucleon.Comment: 9 pages, 3 figures. Talk presented at The 3rd Circum-Pan-Pacific
Symposium on "High Energy Spin Physics" October 8-13 2001, Beijing, Chin
Elliptic flow in Au+Au collisions at = 130 GeV
We report the elliptic flow of charged and identified particles at
mid-rapidity in Au+Au collisions at GeV using the STAR
TPC at RHIC. The integrated elliptic flow signal, , for charged particles
reaches values of about 0.06, indicating a higher degree of thermalization than
at lower energies. The differential elliptic flow signal, () up to
1.5 GeV/, shows a behavior expected from hydrodynamic model calculations.
Above 1.5 GeV/, the data deviate from the hydro predictions; however the
() is still large, suggesting finite asymmetry for the products of
hard scattering. For the identified particles, elliptic flow as a function of
and centrality differ significantly for particles of different masses.
This dependence can be accounted for in hydrodynamic models, indicating that
the system created shows a behavior consistent with collective hydrodynamical
flow.Comment: 6 pages, 8 figures, Quark Matter 200
Measurements of Photon and Neutral Pion Production in Heavy Ion Collisions at RHIC
Inclusive transverse momentum spectra of photons and neutral pions about
mid-rapidity are presented for Au+Au collisions at sqrt(s_NN} = 130 GeV. Photon
pair conversions have been reconstructed from charged tracks measured with the
central Time Projection Chamber (TPC) of STAR. Contributions of the pi^0 ->
\gamma\gamma decay in the inclusive photon spectra have been studied. It was
found that this contribution begins to decrease at a transverse momentum of
1.65 GeV/c in the top 11% most central centrality class.Comment: 5 pages, 3 figures, contribution to the Proceedings of Quark Matter
2002, Nantes, France, July 18-24, 200
Baryon and antibaryon production in hadron-hadron and hadron-nucleus interactions
Cascade baryon and anti-baryon yields have been measured in p+p and p+A
collisions. After extraction of the projectile component in p+A interactions
close similarities with A+A collisions concerning the nuclear enhancement
factors are observed. In addition the importance of effects related to
projectile isospin and to net baryon stopping is pointed out.Comment: 4 pages, 5 figures, Presented at Quark Matter 2002, Nantes, Franc
Elementary Hadronic Interactions at the CERN SPS
New data from the NA49 experiment at the CERN SPS concerning hadron+proton
and hadron+nucleus interactions are discussed and compared to nucleus+nucleus
collisions. Detailed information on baryonic momentum distributions and nuclear
enhancement factors for kaons and cascade baryons are extracted.Comment: 11 pages, 9 figures, to be published in the Proceedings of the XVIth
International Conference on Ultrarelativistic Nucleus-Nucleus Collisions
"Quark Matter 2002", Nantes, France, July 200
Resonance Production in STAR
The recent results from resonance production in central Au+Au and p+p
collisions at 200 GeV from the STAR experiment at RHIC
are presented and discussed.Comment: 7 pages, proceedings 19th Winter Workshop on Nuclear Dynamics,
Breckenridge, Colorado, USA, February 8-15, 200
Correlations, Fluctuations, and Flow Measurements from the STAR Experiment
New measurements of short-range and long-range two-particle correlations,
azimuthal anisotropy, and event-by-event fluctuations from the STAR experiment
for sqrt{s_{NN}}= 130 and 200 GeV Au+Au collisions are summarized. Striking
evidence is presented for large, non-statistical fluctuations in mean
transverse momentum. Descriptions of the data in terms of phenomenological
source function models are also presented.Comment: 10 pages, 10 figures, Conference proceedin
System size dependence of strangeness production at 158 AGeV
Strange particle production in A+A interactions at 158 AGeV is studied by the
CERN experiment NA49 as a function of system size and collision geometry.
Yields of charged kaons, phi and Lambda are measured and compared to those of
pions in central C+C, Si+Si and centrality-selected Pb+Pb reactions. An overall
increase of relative strangeness production with the size of the system is
observed which does not scale with the number of participants. Arguing that
rescattering of secondaries plays a minor role in small systems the observed
strangeness enhancement can be related to the space-time density of the primary
nucleon-nucleon collisions.Comment: 5 pages, 3 figures, Presented at Quark Matter 2002, Nantes, Franc
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