Fluctuations of Charge Separation Perpendicular to the Event Plane and Local Parity Violation in Root S-NN=200 GeV Au + Au Collisions at the BNL Relativistic Heavy Ion Collider
Previous experimental results based on data (similar to 15 x 10(6) events) collected by the STAR detector at the BNL Relativistic Heavy Ion Collider suggest event-by-event charge-separation fluctuations perpendicular to the event plane in noncentral heavy-ion collisions. Here we present the correlator previously used split into its two component parts to reveal correlations parallel and perpendicular to the event plane. The results are from a high-statistics 200-GeV Au + Au collisions data set (57 x 10(6) events) collected by the STAR experiment. We explicitly count units of charge separation from which we find clear evidence for more charge-separation fluctuations perpendicular than parallel to the event plane. We also employ a modified correlator to study the possible P-even background in same- and opposite-charge correlations, and find that the P-even background may largely be explained by momentum conservation and collective motion.
Drachenberg, James L.; Gibson, Adam; Grosnick, David; Koetke, Donald D.; Stanislaus, Shirvel; and Star Collaboration, "Fluctuations of Charge Separation Perpendicular to the Event Plane and Local Parity Violation in Root S-NN=200 GeV Au + Au Collisions at the BNL Relativistic Heavy Ion Collider" (2013). Physics and Astronomy Faculty Publications. 48.