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 centre-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, |PΛ| < 0.01, is significantly below the theoretical values discussed recently in the literature.

Abstract. Yields and spectra of Σ(1385) are measured in p + p, d + Au and Au + Au collisions at √ s NN =200 GeV. The nuclear modification factors in d + Au collisions are presented. The p T dependent medium effects are investigated via the nuclear modification factors. The implications of these results on various models are discussed.

Abstract. In this proceedings we present STAR measurements of two particle azimuthal correlations between trigger particles at mid-rapidity (|η| < 1) and associated particles at forward rapidities (2.7 < |η| < 3.9) in p+p, d+Au and Au+Au collisions at √ s N N = 200 GeV. Two particle azimuthal correlations between a midrapidity trigger particle and forward-rapidity associated particles preferably probe large-x quarks scattered off small-x gluons in RHIC collisions. Comparison of the separate d-and Au-side measurements in d+Au collisions may potentially probe gluon saturation and the presence of Color Glass Condensate. In Au+Au collisions quark energy loss can be probed at large rapidities, which may be different from gluon energy loss measured at mid-rapidity.

The STAR Collaboration) We report STAR measurements of the longitudinal double-spin asymmetry ALL, the transverse single-spin asymmetry AN , and the transverse double-spin asymmetries AΣ and AT T for inclusive jet production at mid-rapidity in polarized p + p collisions at a center-of-mass energy of √ s = 200 GeV.The data represent integrated luminosities of 7.6 pb −1 with longitudinal polarization and 1.8 pb −1 with transverse polarization, with 50-55% beam polarization, and were recorded in 2005 and 2006.No evidence is found for the existence of statistically significant jet AN , AΣ, or AT T at midrapidity. Recent model calculations indicate the AN results may provide new limits on the gluon Sivers distribution in the proton. The asymmetry ALL significantly improves the knowledge of gluon polarization in the nucleon.

A variety of particle species measured by the STAR experiment in 200 GeV Au+Au collisions yielded rich information about freeze-out dynamics at RHIC. The results on chemical and kinetic freeze-out properties and their centrality dependences appeared to be consistent with QGP formation in the early stage of the collision. To further advance our understanding of the collision evolution, lower energy 62.4 GeV Au+Au collisions were measured. Here, we present a review of freeze-out dynamics in 200 GeV collisions at RHIC in comparison with new results from the 62.4 GeV data.