in HBT analyses.

Small-momentum-scale correlation structures due to quantum, Coulomb and strong-interaction correlations [@starhbt] were suppressed by eliminating sibling [*and*]{} mixed track pairs ($\sim$22% of total) with $|\eta_{\Delta}| < 1.0$, $|\phi_{\Delta}| < 1.0$ and $|p_{t1} - p_{t2}| < 0.2$ GeV/$c$ if $p_t < 0.8$ GeV/$c$ for either particle. Those cuts do not significantly affect the correlation structures shown here. Four centrality classes for 300k events labeled (a) - (d) for central to peripheral were defined by cuts on TPC track multiplicity $N$ within the acceptance defined here relative to minimum-bias event multiplicity frequency distribution upper half-maximum end-point $N_0$, which corresponds to the maximum participant number [@meanptprl; @nu]. Four centrality classes were defined by (d) $0.03 < N/N_0 \leq 0.21$, (c) $0.21 < N/N_0 \leq 0.56$, (b) $0.56 < N/N_0 \leq 0.79$ and (a) $N/N_0 > 0.79$.

![\[Figure1\] Normalized LS pair-number ratios $\hat{r}$ for collisions in centrality class (a) (most central) for $(\eta_1,\eta_2)$ (left panel) and $(\phi_1,\phi_2)$ (right panel). ](mtxmtlsus3 "fig:"){width="1.65in"} ![\[Figure1\] Normalized LS pair-number ratios $\hat{r}$ for collisions in centrality class (a) (most central) for $(\eta_1,\eta_2)$ (left panel) and $(\phi_1,\phi_2)$ (right panel). ](mtxmtlsus1 "fig:"){width="1.65in"}

Two-particle Distributions {#2part}
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Fig. \[Figure1\] shows ratio histograms $\hat r_{ab}$ for the LS charge combination 