CERN Accelerating science

Trigger turn-on curves: the ratio of inclusive electrons in EMCal triggered events to minimum-bias events as a function of associated track \pt\ in centrality bins between 0\% and 50\%. The lower right panel shows a similar ratio obtained with EMCal clusters for centrality 50--80\%. The \pt\ from which the spectra from the minimum-bias trigger to the EMCal trigger are used are indicated with black dashed lines. The scaling factors which were obtained by fits (red lines) are summarized in Table \ref{tab:rejectionFactors}.

{\it \bf Left:} The ratio of $E/p$ as a function of $n_{\sigma}^{\mathrm{TPC}}$ in 10\% most central Pb--Pb events ($p_{\textrm{T}}>$ 3 GeV/$c$), where $p$ is the charged particle momentum, $E$ is the matched EMCal cluster energy, and $\sigma^{\mathrm{TPC}}$ is the resolution on the energy loss in the TPC gas expected for electrons. {\it \bf Right:} $E/p$ for electrons in two transverse momentum ranges. The blue open symbols shows the hadron contamination -- an $E/p$ distribution for particles 3.5 $\sigma$ away from the mean of the true electron ${\rm TPC}$-d$E$/d$x$ distribution normalized to the electron $E/p$ at small values of the ratio (away from the electron signal).

{\it \bf Left:} Product of detector acceptance and reconstruction efficiency for inclusive electrons as a function of the electron \pt. The statistical uncertainty is smaller than the size of the points. {\it \bf Right:} Photonic electron reconstruction efficiency via invariant mass ($\epsilon_{e^{\gamma}}$) as a function of \pt\ of the electron.

Differential yields of electrons from semi-leptonic decays of heavy-flavour hadrons in classes of centrality of \PbPb\ collisions at \sqrtsnn{2.76}.

\RPBPB\ of electrons from heavy-flavour hadron decays in centrality bins of \PbPb\ collisions at \sqrtsnn{2.76}. The solid band at $\RPBPB=1$ brackets the uncertainty on the average nuclear overlap function ($\langle T_{\rm{AA}} \rangle$).

{\it \bf Left:} \RPBPB\ of electrons and muons \cite{Abelev:2012qh} from heavy-flavour hadron decays in 10\% most central \PbPb\ collisions shown together with \RpPb\ of electrons from minimum bias proton-lead collisions at \sqrtsnn{5.02} \cite{Adam:2015qda}. {\it \bf Right:} \RPBPB\ of electrons in semi-peripheral \PbPb\ collisions (50--80\% selection for electrons and 40--80\% for muons.

\RPBPB\ of electrons from heavy-flavour hadron decays measured in 10\% most central \PbPb\ collisions at \sqrtsnn{2.76} compared to various theoretical calculations~\cite{Djordjevic:2014tka,Wicks:2005gt,Horowitz:2011gd,Horowitz:2011wm,Sharma:2009hn,He:2014cla,Cao:2013ita,Nahrgang:2013xaa,Alberico:2011zy,Beraudo:2014boa,Uphoff:2011ad,Fochler:2011en,Uphoff:2012gb}.