Results on charge multiplicity asymmetry in Au+Au and d+Au collisions at 200 GeV by the STAR experiment are reported. It was found that the correlation results could not be explained by CME alone. Additionally, the charge separation signal as a function of the measured azimuthal angle range as well as the event-by-event anisotropy parameter are studied. These results indicate that the charge separation effect appears to be in-plane rather than out-of-plane. It is discovered that the charge separation effect is proportional to the event-by-event azimuthal anisotropy and consistent with zero in events with zero azimuthal anisotropy.

These studies suggest that the charge separation effect, within the statistical error, may be a net effect of event anisotropy and correlated particle production. A potential upper limit on the CME is also presented through this data.