Figure 3

Nuclear modification factor $R_{\rm{AA}} $ of charged particles as a function of $\langle N_{{\rm{part}}} \rangle$ (top panel) and ${\rm{d}}{N_{\rm{ch}}}/\rm{d}\eta$ (bottom panel) measured by ALICE in Pb-Pb collisions indifferent $\pt$-intervals, compared to PHENIX results in $5< \pt< 7$GeV/$c$ . The boxes around the data representthe $p_{\rm T}$-dependent uncertainties on the Pb-Pb $p_{\rm T}$ spectra. The boxes at $R_{\rm{AA}} =1$ represent the systematic uncertainties on the pp reference in different $\pt$-intervals ($p_{\rm{T}}$-interval increases from left to right, the left-most is for PHENIX). The systematicuncertainties on the overall normalization for ALICE and PHENIX are not shown.