Influence of the non-flow effects and fluctuations on the v2 measurements at RHIC

The cumulant method is applied to study elliptic flow (v2) in Au+Au collisions at s = 200 AGeV, with the UrQMD model. We find that the four and six-particle cumulants are good measures of the real elliptic flow over a wide range of centralities except for the most central and very peripheral events. There the cumulant method is affected by the v2 fluctuations. In mid-central collisions, the four and six-particle cumulants are shown to give a good estimation of the true differential v2, especially at large transverse momentum, where the two-particle cumulant method is heavily affected by the non-flow effects.