Parity-odd domains, corresponding to non-trivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system's orbital momentum axis. We investigate a three particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au+Au and Cu+Cu collisions at √ sNN =200 GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation.

The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.

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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