Physical Review C
A study is reported of the same-and opposite-sign charge-dependent azimuthal correlations with respect to the event plane in Au+ Au collisions at √ˢᶰᶰ = 200 GeV. The charge multiplicity asymmetries between the up/down and left/right hemispheres relative to the event plane are utilized. The contributions from statistical fluctuations and detector effects were subtracted from the (co-) variance of the observed charge multiplicity asymmetries. In the mid-to most-central collisions, the same- (opposite-) sign pairs are preferentially emitted in back-to-back (aligned on the same-side) directions. The charge separation across the event plane, measured by the difference, Δ, between the like-and unlike-sign up/down-left/right correlations, is largest near the event plane. The difference is found to be proportional to the event-by-event final-state particle ellipticity (via the observed second order harmonic vobs2, where Δ = [ 1.3 ± 1.4(stat) +4.0 -1.0(syst)] x 10-5 + [3.2 ± 0.2(stat) +0.4-0.3 (syst)] x 10-3 vobs2 for 20- 40% Au + Au collisions. The implications for the proposed chiral magnetic effect are discussed.
Original Publication Citation
Adamczyk, L., Adkins, J. K., Agakishiev, G., Aggarwal, M. M., Ahammed, Z., Alakhverdyants, A. V., . . . Collaboration, S. (2014). Measurement of charge multiplicity asymmetry correlations in high-energy nucleus-nucleus collisions at √ˢᶰᶰ = 200 GeV. Physical Review C, 89(4), 044908. doi:10.1103/PhysRevC.89.044908
Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Bültmann, S.; and STAR Collaboration, "Measurement of Charge Multiplicity Asymmetry Correlations in High-Energy Nucleus-Nucleus Collisions at √ˢᶰᶰ = 200 GeV" (2014). Physics Faculty Publications. 185.