represented by the solid dot in the left panel at $\nu = 1$. Comparison of the low-$p_t$ ($0.15 \leq p_t \leq 0.5$ GeV/c) p-p results with the present Au-Au results is qualitative but reasonable given the similarity in shape of the Au-Au CD correlations for $0.15 \leq p_t \leq 0.5$ (discussed below) to those in Fig. \[Figure2\].

The collision centrality is represented by mean participant path length $\nu$ [@nu], defined as the average number of nucleons encountered by a participant nucleon. That centrality measure is desirable because it permits comparisons with p-A collisions, initial-state scattering should follow a trend linear in $\nu$ and $\nu$ also provides an estimate (proportionality) of final-state pathlength.

We adopt the strategy of plotting $\tan^{-1}(\sigma_{\phi_\Delta})$ rather than $\sigma_{\phi_\Delta}$ so as to include the p-p ‘infinite azimuth width’ on the same plot, since that distribution is approximately uniform on $\phi$. Interpolations among the measured Au-Au points are sketched by the solid and dash-dot curves. [*Extrapolations*]{} to corresponding p-p values are sketched by the dashed and dotted curves. The extrapolations contain [*substantial uncertainties*]{} in relating p-p to mid-peripheral Au-Au results. *Efficiency-corrected*

per-particle correlation amplitudes $\tilde S\bar NA$ for central Au-Au collisions exceed in magnitude those for p-p collisions 