Pion efficiency as a function of electron efficiency (left, for 6 detector layers) and as a function of the number of detector layers (right, for 90\% electron efficiency) for the various eID methods The results are compared for the momentum interval 0.9--1.1\gevc in \ppb collisions at \sqrtsnn = 5.02 TeV. The results of the truncated mean method are only shown for a minimum of 4 tracklets, where the resolution is better than 18\% (see Fig. \ref{Figure_truncmeanres}).