233 research outputs found
Single spin asymmetry measurements for inclusive productions in and \pi^-+\p_{\uparrow}\to \pi^0+X reactions at 70 and 40 GeV respectively
The inclusive asymmetries were measured in reactions and at 70 and 40 GeV/c respectively. The
measurements were made at the central region (for the first reaction) and
asymmetry is compatible with zero in the entire measured region. For the
second reaction the asymmetry is zero for small region () and increases with growth of . Averaged
over the interval the asymmetry was .Comment: 4 pages, 2 figures; Presented at SPIN-2004 at Trieste, October
10-16,200
Correlations in STAR: interferometry and event structure
STAR observes a complex picture of RHIC collisions where correlation effects
of different origins -- initial state geometry, semi-hard scattering,
hadronization, as well as final state interactions such as quantum intensity
interference -- coexist. Presenting the measurements of flow, mini-jet
deformation, modified hadronization, and the Hanbury Brown and Twiss effect, we
trace the history of the system from the initial to the final state. The
resulting picture is discussed in the context of identifying the relevant
degrees of freedom and the likely equilibration mechanism.Comment: 8 pages, 6 figures, plenary talk at the 5th International Conference
on Physics and Astrophysics of Quark Gluon Plasma, to appear in Journal of
Physics G (http://www.iop.org
Neutral Kaon Interferometry in Au+Au collisions at sqrt(s_NN) = 200 GeV
We present the first statistically meaningful results from two-K0s
interferometry in heavy-ion collisions. A model that takes the effect of the
strong interaction into account has been used to fit the measured correlation
function. The effects of single and coupled channel were explored. At the mean
transverse mass m_T = 1.07 GeV, we obtain the values R = 4.09 +/- 0.46 (stat.)
+/- 0.31 (sys) fm and lambda = 0.92 +/- 0.23 (stat) +/- 0.13 (sys), where R and
lambda are the invariant radius and chaoticity parameters respectively. The
results are qualitatively consistent with m_T systematics established with
pions in a scenario characterized by a strong collective flow.Comment: 11 pages, 10 figure
Azimuthal anisotropy and correlations at large transverse momenta in p+p and Au+Au collisions at sqrt[sNN] = 200 GeV
Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au+Au collisions at sqrt[sNN]=200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au+Au collisions to those in p+p at the same energy. The elliptic anisotropy v2 is found to reach its maximum at pt~3 GeV/c, then decrease slowly and remain significant up to pt ~ 7-10 GeV/c. Stronger suppression is found in the back-to-back high-pt particle correlations for particles emitted out of plane compared to those emitted in plane. The centrality dependence of v2 at intermediate pt is compared to simple models based on jet quenching
Strangelet search at RHIC
Two position sensitive Shower Maximum Detector (SMDs) for Zero-Degree
Calorimeters (ZDCs) were installed by STAR before run 2004 at both upstream and
downstream from the interaction point along the beam axis where particles with
small rigidity are swept away by strong magnetic field. The ZDC-SMDs provides
information about neutral energy deposition as a function of transverse
position in ZDCs. We report the preliminary results of strangelet search from a
triggered data-set sampling 100 million Au+Au collisions at top RHIC energy.Comment: Strange Quark Matter 2004 conference proceedin
Pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV
We present a systematic analysis of two-pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV using the STAR detector at Relativistic Heavy Ion Collider. We extract the Hanbury-Brown and Twiss radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianness of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast-wave parametrizations. The expansion of the source and its relation with the initial energy density distribution is studied
- …