Global polarization of Λ hyperons has been measured to be of the order of a few tenths of a percent in Au+Au collisions at √ s N N = 200 GeV, with no significant difference between Λ andΛ.These new results reveal the collision energy dependence of the global polarization together with the results previously observed at √ s N N = 7.7 -62.4 GeV and indicate noticeable vorticity of the medium created in non-central heavy-ion collisions at the highest RHIC collision energy. The signal is in rough quantitative agreement with the theoretical predictions from a hydrodynamic model and from the AMPT (A Multi-Phase Transport) model. The polarization is larger in more peripheral collisions, and depends weakly on the hyperon's transverse momentum and pseudorapidity η H within |η H | < 1. An indication of the polarization dependence on the event-by-event charge asymmetry 3 is observed at the 2σ level, suggesting a possible contribution to the polarization from the axial current induced by the initial magnetic field. PACS numbers: 25.75.-q, 25.75.Ld

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We report new STAR measurements of the single-spin asymmetries AL for W + and W − bosons produced in polarized proton-proton collisions at √ s = 510 GeV as a function of the decay-positron and decay-electron pseudorapidity. The data were obtained in 2013 and correspond to an integrated luminosity of 250 pb −1 . The results are combined with previous results obtained with 86 pb −1 . A comparison with theoretical expectations based on polarized lepton-nucleon deep-inelastic scattering and prior polarized proton-proton data suggests a difference between the ū and d quark helicity distributions for 0.05 < x < 0.25. In addition, we report new results for the double-spin asymmetries ALL for W ± , as well as AL for Z/γ * production and subsequent decay into electron-positron pairs.