Elliptic Flow of $\pi^–$ Measured with the Event Plane Method in Pb–Pb Collisions at 40A Ge in the NA49 Experiment at the CERN SPS

The measurement of elliptic flow for negatively charged pions in Pb-Pb collisions at beam energy of 40 A GeV performed with the fixed target experiment NA49 at the CERN SPS is presented. Results are compared with measurements at similar energies by the STAR experiment at RHIC. Elliptic flow is measured using the event plane method. The event plane angle is estimated using negatively charged pion tracks reconstructed in the Time Projection Chambers (TPC) and from energies measured in the cells of the Ring Calorimeter (RCAL). In future, these results will be used as a reference for flow measurements in the lead ion energy scan program of the NA61/SHINE experiment at the CERN SPS.