NUKLEONIKA 2006, 51(Suppl. 3):s37-s41

INFLUENCE OF THE NON-FLOW EFFECTS AND FLUCTUATIONS ON THE v2 MEASUREMENTS AT RHIC

Xianglei Zhu1,2,3, Marcus Bleicher2

1 Frankfurt Institute for Advanced Studies (FIAS)
2 Institut für Theoretische Physik, Johann Wolfgang Goethe-Universität, 1 Max-von-Laue-Str., D-60438 Frankfurt am Main, Germany
3 Physics Department, Tsinghua University, Beijing 100084, China

The cumulant method is applied to study elliptic flow (v2) in Au+Au collisions at Ös = 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.