Forward-backward elliptic anisotropy correlations in parton cascades

A potential experimental probe, the forward-backward elliptic anisotropy correlation (C(FB)), has been proposed by Liao and Koch to distinguish the jet and true elliptic flow contribution to the measured elliptic flow (v(2)) in relativistic heavy-ion collisions. The jet and flow fluctuation contribution to elliptic flow is investigated within the framework of a multiphase transport model using the C(FB) probe. We find that the C(FB) correlation is remarkably different from, and about two times that, proposed by Liao and Koch. It originates from the correlation between fluctuation of forward and that of backward elliptic flow at a low transverse momentum, which is mainly caused by the initial correlation between fluctuation of forward and that of backward eccentricity. This results in an amendment of the C(FB) by a term related to the correlation between fluctuation of forward and that of backward elliptic flow. Our results suggest that a suitable rapidity gap for C(FB) correlation studies is about +/- 3.5.