  STAR has recently reported charge-dependent azimuthal correlations that are
sensitive to the charge separation effect in Au+Au collisions at $\sqrt{s_{\rm
NN}}$ = 200 GeV. Qualitatively, these results agree with some of the
theoretical predictions for local parity violation in heavy-ion collisions.
However, a study using reaction-plane-dependent balance functions shows an
alternative origin of this signal. The balance function, which measures the
correlation between oppositely charged pairs, is sensitive to the mechanisms of
charge formation and the subsequent relative diffusion of the balancing
charges. The reaction-plane-dependent balance function measurements can be
related to STAR's charge-dependent azimuthal correlations. We report
reaction-plane-dependent balance functions for Au+Au collisions at
$\sqrt{s_{\rm NN}}$ = 200, 62.4, 39, 11.5, and 7.7 GeV using the STAR detector.
The model of Schlichting and Pratt incorporating local charge conservation and
elliptic flow reproduces most of the three-particle azimuthal correlation
results at 200 GeV. The experimental charge-dependent azimuthal charge
correlations observed at 200 GeV can be explained in terms of local charge
conservation and elliptic flow.

Nuclear Experiment