Scaling Properties of Proton and Antiproton Production in $\sqrt{s_{NN}}=200\mathrm{G}\mathrm{e}\mathrm{V}$ $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ Collisions

We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$ collisions at $\sqrt{s_{NN}}=200\mathrm{G}\mathrm{e}\mathrm{V}$ measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta ($1.5<p_T<4.5\mathrm{G}\mathrm{e}\mathrm{V}/c$) a significant fraction of all produced particles are protons and antiprotons. They show a centrality-scaling behavior different from that of pions. The $\overline{p}/\pi$ and $p/\pi$ ratios are enhanced compared to peripheral $\mathrm{A}\mathrm{u}+\mathrm{A}\mathrm{u}$, $p+p$, and $e^{+}{e}^{-}$ collisions. This enhancement is limited to $p_T<5\mathrm{G}\mathrm{e}\mathrm{V}/c$ as deduced from the ratio of charged hadrons to ${\pi }^0$ measured in the range $1.5<p_T<9\mathrm{G}\mathrm{e}\mathrm{V}/c$.