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Differential measurements of elliptic flow (v2) for Au+Au and Cu+Cu collisions at sqrt[sNN]=200 GeV are used to test and validate predictions from perfect fluid hydrodynamics for scaling of v2 with eccentricity, system size, and transverse kinetic energy (KE T). For KE T identical with mT-m up to approximately 1 GeV the scaling is compatible with(More)
The possibility of obtaining transverse polarization with colliding beams was studied at LEP during 1994. A level of transverse beam polarization of 40% was achieved with e + e collisions in one of the experimental interaction points. the collision of one electron and one positron bunch was 1:5 10 30 cm 2 s 1. The polarization level was not limited by the(More)
New data are presented on charged particle pseudorapidity distributions for inelastic events produced at c.m. energies ]//s=200 and 900 GeV. The data were obtained at the CERN antiproton-proton Collider operated in a new pulsed mode. The rise of the central density p(0) at energies up to ]fs = 900 GeV has been studied. A new form of central region scaling(More)
In a joint experiment the TAPS and CERES collaborations have studied the production of the neutral mesons ; and ! in 450 GeV p-Be and p-Au collisions at the CERN SPS. The mesons were identiied by their ! , ! , and ! ! decay modes. The cross sections were measured down to very low p T (20 MeV/c) near mid-rapidity (3:0 < y < 4:0). The and ! cross sections are(More)
Back-to-back hadron pair yields in d+Au and p+p collisions at √s(NN)=200 GeV were measured with the PHENIX detector at the Relativistic Heavy Ion Collider. Rapidity separated hadron pairs were detected with the trigger hadron at pseudorapidity |η|<0.35 and the associated hadron at forward rapidity (deuteron direction, 3.0<η<3.8). Pairs were also detected(More)
The double helicity asymmetry in neutral pion production for pT=1 to 12 GeV/c was measured with the PHENIX experiment to access the gluon-spin contribution, DeltaG, to the proton spin. Measured asymmetries are consistent with zero, and at a theory scale of micro2=4 GeV2 a next to leading order QCD analysis gives DeltaG[0.02,0.3]=0.2, with a constraint of(More)
In a joint eeort the CERES/NA45 and TAPS collaborations have measured low-mass electron pairs in p{Be and p{Au collisions at 450 GeV/c at the CERN SPS. In the range covered up to 1.5 GeV/c 2 the mass spectra from p{Be and p{Au collisions are well explained by electron pairs from decays of neutral mesons. For p{Au our result is new. For p{Be, the(More)
Transverse single-spin asymmetries to probe the transverse-spin structure of the proton have been measured for neutral pions and nonidentified charged hadrons from polarized proton-proton collisions at midrapidity and square root(s) = 200 GeV. The data cover a transverse momentum (pT) range 1.0-5.0 GeV/c for neutral pions and 0.5-5.0 GeV/c for charged(More)
Transverse momentum spectra of neutral pions in the range 1<p(T)<10 GeV/c have been measured at midrapidity by the PHENIX experiment at BNL RHIC in Au+Au collisions at sqrt[s(NN)]=200 GeV. The pi(0) multiplicity in central reactions is significantly below the yields measured at the same sqrt[s(NN)] in peripheral Au+Au and p+p reactions scaled by the number(More)