Figure 2

The $p_{\rm T}$-differential invariant yields of electrons from semileptonic heavy-flavour hadron decays measured at mid-rapidity in 0--10\% and 20--40\% central Pb--Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV. Statistical uncertainties are smaller than the symbol size and the systematic uncertainties are shown as boxes.