Figure 1

(a) Distribution of event plane angle $\psi_2$, estimated from TPC tracks with $0< \eta< 0.8$ (solid line) or with the VZERO detector signals (dashed line) in the centrality range 30--50\%. The distributions are normalized by their integral.

(b) Event plane resolution correction factor $R_2$ as a function of centrality for the TPC and VZERO detectors. The boxes represent the systematic uncertainties estimated from the variation of $R_2$ when changing the sub-events used for its determination.