2,017 research outputs found
Anisotropic Flow at the SPS and RHIC
The results on directed and elliptic flow for Pb + Pb at the full energy of
the SPS (158 GeV/A) and from the first year of Au + Au at RHIC
(sqrt{s_{_{NN}}=130 GeV) are reviewed. The different experiments agree well and
a consistent picture has emerged indicating early time thermalization at RHIC.Comment: 4 pages. For the proceedings of the International Workshop on the
Physics of the Quark-Gluon Plasma, Palaiseau, France, 4-7 Sept. 0
Directed and Elliptic Flow in Pb+Pb collisions at 40 and 158 AGeV
Directed and elliptic flow are reported for charged pions and protons as a
function of transverse momentum, rapidity, and centrality in 40 and 158 AGeV Pb
+ Pb collisions. The standard method of correlating particles with an event
plane is used. The directed flow of protons is small and shows little variation
near to midrapidity, but rises fast towards projectile rapidity in the 40 AGeV
data. For most peripheral collisions the flat region becomes negative resulting
in changing sign three times. Elliptic flow doesn't seem to change very
much from 40 AGeV to 158 AGeV. The difference is smaller than anticipated from
the overall energy dependence from AGS to RHIC.Comment: Presented at 16th International Conference on Ultrarelativistic
Nucleus-Nucelus Collisions, Quark Matter 2002 (QM 2002), Nantes, France,
18-24 Jul 2002, 4 pages, 3 figure
Forward-rapidity azimuthal and radial flow of identified particles for = 200 GeV Au+Au collisions
A strong azimuthal flow signature at RHIC suggests rapid system equilibration
leading to an almost perfect fluid state. The longitudinal extent of the flow
behavior depends on how this state is formed and can be studied by measuring
the pseudorapidity and transverse momentum dependence of the second Fourier
component () of the azimuthal angular distribution. We report on
a measurement of identified-particle as a function of (0.5-2.0
GeV/c), centrality (0-25%, 25-50%), and pseudorapidity () for
Au+Au collisions. The BRAHMS spectrometers are
used for particle identification (, K, p) and momentum determination and
the BRAHMS global detectors are used to determine the corresponding
reaction-plane angles. The results are discussed in terms of the rapidity
dependence of constituent quark scaling and in terms of models that develop the
complete (azimuthal and radial) hydrodynamic aspects of the forward dynamics at
RHIC.Comment: 4 pages, 4 figures - To appear in the conference proceedings for
Quark Matter 2009, March 30-April 4, Knoxville, Tennesse
Effect of flow fluctuations and nonflow on elliptic flow methods
We discuss how the different estimates of elliptic flow are influenced by
flow fluctuations and nonflow effects. It is explained why the event-plane
method yields estimates between the two-particle correlation methods and the
multiparticle correlation methods. It is argued that nonflow effects and
fluctuations cannot be disentangled without other assumptions. However, we
provide equations where, with reasonable assumptions about fluctuations and
nonflow, all measured values of elliptic flow converge to a unique mean
v_{2,PP} elliptic flow in the participant plane and, with a Gaussian assumption
on eccentricity fluctuations, can be converted to the mean v_{2,RP} in the
reaction plane. Thus, the 20% spread in observed elliptic flow measurements
from different analysis methods is no longer mysterious.Comment: one typo in Table I correcte
Collective phenomena in non-central nuclear collisions
Recent developments in the field of anisotropic flow in nuclear collision are
reviewed. The results from the top AGS energy to the top RHIC energy are
discussed with emphasis on techniques, interpretation, and uncertainties in the
measurements.Comment: Review paper, 56 pages, as accepted for publicatio
Centrality dependence of directed and elliptic flow at the SPS
New data with a minimum bias trigger for 158 GeV/nucleon Pb + Pb have been analyzed. Directed and elliptic flow as a function of rapidity of the particles and centrality of the collision are presented. The centrality dependence of the ratio of elliptic flow to the initial space elliptic anisotropy is compared to models
Measurement of Event Plane Correlations in Pb-Pb Collisions at =2.76 TeV with the ATLAS Detector
A measurement of correlations between event-plane angles is
presented as a function of centrality for Pb-Pb collisions at
TeV. These correlations are estimated from
observed event-plane angles obtained from charged particle or
transverse energy flow measured over a large pseudorapidity range ,
followed by a resolution correction that accounts for the dispersion of
relative to . Various correlators involving two or three event
planes with acceptable resolution are measured. Significant positive
correlations are observed for , ,
, , and
. However, the measured correlations for
are negative. These results may shed light on the
patterns of the fluctuation of the created matter in the initial state as well
as the subsequent hydrodynamic evolution.Comment: 5 pages, 4 figures. Proceedings for Hard Probes 2012, Cagliari, Ital
The Effect of Neuromuscular Training and Scapular Stabilization Exercises in a Young Active Male with Anterior Shoulder Instability: A Case Report
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