Search for local parity violation with STAR ZDC-SMD

Parity-odd domains are predicted to lead to charge separation of quarks along the orbital momentum of the system created in non-central relativistic heavy ion collisions. A signal consistent with several of the theoretical expectations has been detected by STAR, with a three particle azimuthal correlator which is a -even observable, but still sensitive to the charge separation effect. In this correlator, the first two particles are used to reveal the physics of interest, and the third particle serves as a reference for the reaction plane. In this work, to minimize the non-parity correlation between the third particle and the first two, we utilize the spectator neutrons detected by STAR ZDC-SMDs to define the event plane. The 1st-order event plane thus obtained can also be used to study the global strong parity violation effect, and to provide further systematic checks for this analysis. We report measurements of both -even and -odd observables using the STAR ZDC-SMDs in Au+Au at 200 GeV. The results are presented as a function of collision centrality, particle separation in rapidity and transverse momentum (p_T). Systematic checks on the impact from the directed flow will also be discussed.