uncertainties in the whole $p_T$ range for every analyzed centrality interval of Cu$+$Au collisions. At $p_T>5$ GeV/$c$ $R_{AB}$ is $\approx 0.4 - 0.5$ in most central collisions. A weak $p_T$ dependence of the measured $R_{AB}$ values can be observed. The suppression of $\pi^0$ and $\eta$ decreases as one moves to more peripheral collisions.

Fig. \[fig:fig5\] compares $R_{AB}$ of $\pi^0$ mesons measured as a function of $p_T$ in ${\mbox{Cu$+$Au}\xspace}$, ${\mbox{Au$+$Au}\xspace}$ [@Adare:2008qa] and ${\mbox{Cu$+$Cu}\xspace}$ [@Adare:2008ad] collisions at $\sqrt{s_{_{NN}}}=200$ GeV and similar $N_{\rm part}$. In central and semi-central ${\mbox{Cu$+$Au}\xspace}$ collisions $\pi^0$ $R_{AB}$ are consistent with those measured in ${\mbox{Au$+$Au}\xspace}$ and ${\mbox{Cu$+$Cu}\xspace}$, if applicable, which suggests that $\pi^0$ suppression mostly depends on the energy density and size of the produced medium. Because in the most central collisions the Cu ion is fully submerged in Au, without any “corona” [@Pantuev:2005jt], but the suppression is the same as in at comparable , the corona-effect is either nonexistent or very small.

In Fig. \[fig:fig6\], the $\pi^0$ and $\eta$ integrated $R_{AB}$’s are shown as a function of $N_{\rm part}$ and compared to ${\mbox{Au$+$Au}\xspace}$. The integration is carried out in two different ranges (${\mbox{$p_T$}\xspace}>5$ and ${\mbox{$p_T$}\xspace}>10$). The results obtained for the two different collision systems are consistent within uncertainties.

