578 research outputs found
ALICE probes of local parity violation with charge dependent azimuthal correlations in Pb-Pb collisions
We report on the measurement of two and three particle azimuthal correlations
in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV recorded with ALICE at the LHC.
While two particle azimuthal correlations mainly provide an important
information on possible background correlations, the three particle correlator
probes the charge separation of hadrons with respect to the collision reaction
plane which is expected for local parity violation in strong interactions. The
two and three particle correlations are presented as a function of collision
centrality and differentially vs. pseudorapidity and transverse momentum, and
provide strong constraints on the possible mechanism of background (parity
conserving) and signal (parity odd) effects in heavy-ion collisions.Comment: Talk given at the 7th Workshop on Particle Correlations and
Femtoscopy (WPCF 2011), 20-24 September 2011, Tokyo, Japan; 6 pages, 3
figure
Photon-jet coincidence measurements in polarized pp collisions at sqrt{s}=200 GeV with the STAR Endcap Calorimeter
Recent inclusive measurements with polarized proton-proton collisions at RHIC
provide significant constraints on the polarized gluon distribution, Delta
g(x), integrated over the gluon momentum range 0.02 < x < 0.3. Di-jet and
photon-jet coincidence measurements will allow to study the x-dependence of
Delta g(x). In this report we present the status of photon-jet coincidence
studies for photons detected at forward pseudorapidity, 1.08<eta<2, using the
STAR Endcap Calorimeter.Comment: Talk given at the Tenth Conference on the Intersections of Particle
and Nuclear Physics (CIPANP 2009), 26-31 May 2009, San Diego CA, USA; 4
pages, 3 figure
Anisotropic flow and other collective phenomena measured in Pb-Pb collisions with ALICE at the LHC
Recent results of the anisotropic flow measurements by the ALICE
Collaboration at the LHC are reviewed. Directed, elliptic, triangular, and
quadrangular flow are presented differentially vs. transverse momentum,
pseudo-rapidity, and the collision centrality for charged and identified
particles. Experimental probes of local parity violation using the charge
dependent azimuthal correlations with respect to the reaction plane are also
discussed.Comment: Talk given at the International Symposium on Multiparticle Dynamics
(ISMD 2011), 26-30 September 2011, AHiroshima (Miyajima Island), Japan; 6
pages, 5 figure
Global polarization measurement in Au+Au collisions
The system created in non central relativistic nucleus-nucleus collisions
carries large angular orbital momentum. Due to spin-orbital coupling, produced
particles could be globally polarized along the direction of the system angular
momentum. We present results of a measurement of Lambda hyperon global
polarization in Au+Au collisions at the center of mass energies 62 and 200 GeV
with the STAR detector at RHIC. The observed global polarization of Lambda
hyperons in the STAR acceptance is consistent with zero within the precision of
the measurement. The obtained upper limit, |P_Lambda| < 0.01, is significantly
below the theoretical values discussed recently in the literature.Comment: Talk given at SQM 2006, International Conference on Strangeness in
Quark Matter, March 26-31, 2006, Los Angeles CA; 4 pages, 2 figure
Charged particle directed flow in Pb-Pb collisions at sqrt{s_NN} = 2.76 TeV measured with ALICE at the LHC
Charged particle directed flow at midrapidity, |eta|<0.8, and forward
rapidity, 1.7 < |eta|<5.1, is measured in Pb-Pb collisions at sqrt{s_NN} = 2.76
TeV with ALICE at the LHC. Directed flow is reported as a function of collision
centrality, charged particle transverse momentum, and pseudo-rapidity. Results
are compared to measurements at RHIC and recent model calculations for LHC
energies.Comment: Talk given at the XXII International Conference on Ultrarelativistic
Nucleus-Nucleus Collisions (Quark Matter 2011), 23-28 May 2011, Annecy,
France; 4 pages, 3 figure
- …