# Figure 1

 Invariant-mass distributions of $\pi$K pairs for pp and the 0-5$\%$ most central Pb-Pb collisions at $\sqrt{s_{\rm{NN}}}$ = 2.76 TeV for the momentum ranges 0.6 < $p_{\rm{T}}$ < 0.9 GeV/$c$ (upper panel) and 10 < $p_{\rm{T}}$ < 15 GeV/$c$ (lower panel), respectively. Panels (a) and (c) show the unlike charge $\pi$K invariant-mass distribution from the same event and normalized mixed event background. Panels (b) and (d) report the invariant-mass distribution after subtraction of the combinatorial background for K$^{*0}$. The statistical uncertainties are shown by bars. The solid curves represent fits to the distributions and the red dashed curves are the components of those fits that describe the residual background