Figure 8

Neutral pion nuclear modification factor, $R_{\rm{AA}}$, in Pb-Pb collisions at $\snn =  2.76 {TeV}$ for the $0-10\%$ class in comparison to results at lower energies. The box around unity reflects the uncertainty of the average nuclear overlap function ($T_{AA}$) and the normalization uncertainty of the pp spectrum added in quadrature. Horizontal bars reflect the bin width. The center-of-mass energy dependence of the neutral pion $R_{\rm{AA}}$ is shown with results from Au-Au collisions at $\snn = 39$, $62.4$ , and $ 200 {GeV}$ as well as the result from the CERN SPS (using scaled p-C data as reference) along with the results for Pb-Pb at $\snn =  2.76 {TeV}$. The scale uncertainties of the measurements at lower energies of the order of $10-15\%$ are not shown.