Table \[TableI\]). In central Au-Au collisions the 1D gaussian peak is no longer detectable. Instead, a large-amplitude 2D negative exponential peak dominates the correlation structure, with similar widths on $\eta_\Delta$ and $\phi_\Delta$ much reduced from those measured in p-p collisions.

![\[Figure4\] Left panel: Efficiency corrected correlation amplitudes for 2D exponential (dots) and 1D gaussian (triangles) components from Table \[TableI\] for negative peaks in Fig. \[Figure2\] are plotted on mean path length $\nu$ [@nu]. Right panel: Fitted widths $\sigma_{\eta_\Delta}$ (dots) and $\tan^{-1}\, \sigma_{\phi_\Delta}$ (triangles) are plotted on $\nu$. Plotting variable $\tan^{-1}$ permits the divergent p-p $\sigma_{\phi_\Delta}$ value to be included. Hatched regions and $\nu = 1$ data points summarize p-p limiting values. Curves guide the eye.](cdcentrality1.eps){width="3.3in"}

Variations of peak amplitudes and widths with Au-Au centrality are shown in Fig. \[Figure4\], along with p-p limiting cases (cross-hatched bands) from STAR p-p data at 200 GeV [@jeffpp], consistent with ISR p-p data at 52.5 GeV [@isrpp]. The p-p data points in Fig. \[Figure4\] (values at $\nu = 1$) indicate the amplitude and r.m.s. width of the 1D gaussian on $\eta_\Delta$, the uniformity of that correlation on $\phi_\Delta$ ($\sigma_{\phi_\Delta} \gg 1$) and the absence of a 2D exponential on $(\eta_\Delta,\phi_\Delta)$ in the fit residuals, 