Figure 1

TPC d$E/$d$x$ signal, expressed in terms of deviation from the expected electron energy loss as a function of momentum (left panel) and fit of the measured $n^{\rm{TPC}}_{\sigma,\rm{e}}$ distribution after the $n^{\rm{TOF}}_{\sigma,\rm{e}}$ requirement in the momentum range 2.9 $< p <$ 3.0 \GeVc (right panel) in pp collisions at $\sqrt{s}$ $=$ 13 TeV for the low-$B$ field data set.