Figure 1

(a): Measured d$E/$d$x$ in the TPC as function of momentum $p$ expressed as a deviation from the expected energy loss of electrons, normalised by the energy-loss resolution ($\sigma_{\rm TPC}$) after eID with TOF. The solid lines indicate the $n_{\sigma}^{TPC}$ selection criteria for the TPC and TOF eID strategy. (b): $E/p$ distribution of electrons ($-1 < n_{\sigma}^{TPC} < 3$) and hadrons ($n_{\sigma}^{TPC} < -3.5$) in the transverse momentum interval $6 < \pt < 8$ GeV/$c$. The $E/p$ distribution of hadrons was normalised to that of electrons in the lower $E/p$ range (0.4-0.6), where hadrons dominate. The solid lines indicate the applied electron selection criteria.