Example of combinatorial background subtracted invariant mass distributions and the extracted yields as a function of $\cos \theta^*$ for $\phi$ and $K^{*0}$ mesons. \textbf{a)} example of $\phi \rightarrow K^+ + K^-$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{b)} example of $K^{*0} (\overline{K^{*0}}) \rightarrow K^{-} \pi^{+} (K^{+} \pi^{-})$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{c)} extracted yields of $\phi$ as a function of $\cos \theta^*$; \textbf{d)} extracted yields of $K^{*0}$ as a function of $\cos \theta^*$.

Example of combinatorial background subtracted invariant mass distributions and the extracted yields as a function of $\cos \theta^*$ for $\phi$ and $K^{*0}$ mesons. \textbf{a)} example of $\phi \rightarrow K^+ + K^-$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{b)} example of $K^{*0} (\overline{K^{*0}}) \rightarrow K^{-} \pi^{+} (K^{+} \pi^{-})$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{c)} extracted yields of $\phi$ as a function of $\cos \theta^*$; \textbf{d)} extracted yields of $K^{*0}$ as a function of $\cos \theta^*$.

Example of combinatorial background subtracted invariant mass distributions and the extracted yields as a function of $\cos \theta^*$ for $\phi$ and $K^{*0}$ mesons. \textbf{a)} example of $\phi \rightarrow K^+ + K^-$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{b)} example of $K^{*0} (\overline{K^{*0}}) \rightarrow K^{-} \pi^{+} (K^{+} \pi^{-})$ invariant mass distributions, with combinatorial background subtracted, integrated over $\cos \theta^*$; \textbf{c)} extracted yields of $\phi$ as a function of $\cos \theta^*$; \textbf{d)} extracted yields of $K^{*0}$ as a function of $\cos \theta^*$.

Efficiency corrected $\phi$-meson yields as a function of cos$\theta$* and corresponding fits with Eq.1 in the method section.

Efficiency and acceptance corrected $K^{*0}$-meson yields as a function of cos$\theta$* and corresponding fits with Eq.4 in the method section.

$\phi$-meson $\rho_{00}$ obtained from 1st- and 2nd-order event planes. The red stars (gray squares) show the $\phi$-meson $\rho_{00}$ as a function of beam energy, obtained with the 2nd-order (1st-order) EP.

$\phi$-meson $\rho_{00}$ with respect to different quantization axes. $\phi$-meson $\rho_{00}$ as a function of beam energy, for the out-of-plane direction (stars) and the in-plane direction (diamonds). Curves are fits based on theoretical calculations with a $\phi$-meson field. The corresponding $G_s^{(y)}$ values obtained from the fits are shown in the legend.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $\phi$ for different collision energies. The gray squares and red stars are results obtained with the 1st- and 2nd-order EP, respectively.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of transverse momentum for $K^{*0}$ for different collision energies.

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

$\rho_{00}$ as a function of centrality for $\phi$ (upper panels) and $K^{*0}$ (lower panels). The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for the $K^{*0}$ meson, obtained with the 2nd-order EP.}

Global spin alignment measurement of $\phi$ and $K^{*0}$ vector mesons in Au+Au collisions at 0-20\% centrality. The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for $K^{*0}$-meson, obtained with the 2nd-order EP.

Global spin alignment measurement of $\phi$ and $K^{*0}$ vector mesons in Au+Au collisions at 0-20\% centrality. The solid squares and stars are results for the $\phi$ meson, obtained with the 1st- and 2nd-order EP, respectively. The solid circles are results for $K^{*0}$-meson, obtained with the 2nd-order EP.

The K$\pi$ pair invariant mass distribution integrated over the $K^{*0}$ $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ =62.4 GeV after mixed-event background subtraction.

The Kπ pair invariant mass distribution for various pT bins (top left) pT = 0.4–0.6 GeV/c in Au+Au collisions at √sNN = 200 GeV after the mixed-event background subtraction.

The Kπ pair invariant mass distribution for various pT bins (top right) pT = 0.6–0.8 GeV/c in Au+Au collisions at √sNN = 62.4 GeV after the mixed-event background subtraction.

The Kπ pair invariant mass distribution for various pT bins (bottom left) pT = 0.8–1.0 GeV/c in Au+Au collisions at √sNN = 200 GeV after the mixed-event background subtraction.

The Kπ pair invariant mass distribution for various pT bins (bottom right) pT = 1.0–1.2 GeV/c in Au+Au collisions at √sNN = 62.4 GeV after the mixed-event background subtraction.

The signal-to-background ratio for $K^{*0}$ measurements as a function of $p_T$ for different collision centrality bins (0-10%, 10-40%, 40-60%, 60-80%) in Au+Au collisions at 200 GeV.

$K^{*0}$ mass as a function of $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV.

$K^{*0}$ mass as a function of $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

$K^{*0}$ mass as a function of $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

$K^{*0}$ mass as a function of $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV

$K^{*0}$ width as a function of $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

$K^{*0}$ width as a function of $p_T$ for minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

$K^{*0}$ width as a function of $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

$K^{*0}$ width as a function of $p_T$ for minimum bias Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV

The $K^{*0}$ reconstruction efficiency multiplied by the detector acceptance as a function of $p_T$ in Au+Au (|$\eta$| < 0.8) collisions at 200 GeV for different collision centrality bins (0-20% ,20-40% , 40-60%)

The $K^{*0}$ reconstruction efficiency multiplied by the detector acceptance as a function of $p_T$ in Cu+Cu (|$\eta$| < 1.0) collisions at 200 GeV for different collision centrality bins (0-20% ,20-40% , 40-60%)

Mid-rapidity $K^{*0}$ $p_T$ spectra for various collision centrality bins (0-20%, 20-40%, 40-60%, 60-80%) in Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

Mid-rapidity $K^{*0}$ $p_T$ spectra for various collision centrality bins (0-20%, 20-40%, 40-60%) in Cu+Cu collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

Mid-rapidity $K^{*0}$ $p_T$ spectra for various collision centrality bins (0-20%, 20-40%, 40-60%, 60-80%) in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Mid-rapidity $K^{*0}$ $p_T$ spectra for various collision centrality bins (0-20%, 20-40%, 40-60%) in Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV

The mid-rapidity yields dN/dy of $K^{*0}$ as a function of the average number of participating nucleons, $⟨N_{part}⟩$, for Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

The mid-rapidity yields dN/dy of $K^{*0}$ as a function of the average number of participating nucleons, $⟨N_{part}⟩$, for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

The mid-rapidity yields dN/dy of $K^{*0}$ as a function of the average number of participating nucleons, $⟨N_{part}⟩$, for Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

The mid-rapidity yields dN/dy of $K^{*0}$ as a function of the average number of participating nucleons, $⟨N_{part}⟩$, for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV

The mid-rapidity $K^{*0}$ $⟨p_T⟩$ as a function $⟨N_{part}⟩$ for Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

The mid-rapidity $K^{*0}$ $⟨p_T⟩$ as a function $⟨N_{part}⟩$ for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 62.4 GeV

The mid-rapidity $K^{*0}$ $⟨p_T⟩$ as a function $⟨N_{part}⟩$ for Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

The mid-rapidity $K^{*0}$ $⟨p_T⟩$ as a function $⟨N_{part}⟩$ for Cu+Cu collisions at $\sqrt{s_{NN}}$ = 200 GeV

The mid-rapidity $⟨p_T⟩$ of $\pi$, K, p and $K^{*0}$ as a function of $⟨N_{part}⟩$ for Au+Au collisions at $\sqrt{s_{NN}}$ = 62.4 GeV.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio for Au+Au at $\sqrt{s_{NN}}$ = 62.4 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio for Cu+Cu at $\sqrt{s_{NN}}$ = 62.4 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio for Au+Au at $\sqrt{s_{NN}}$ = 200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio for Cu+Cu at $\sqrt{s_{NN}}$ = 200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})N(K^-)$ in Au+Au collisions divided by $N(K^{*0})N(K^-)$ ratio in p+p collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$.

Mid-rapidity $N(K^{*0})N(K^-)$ in Cu+Cu collisions divided by $N(K^{*0})N(K^-)$ ratio in p+p collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})N(K^-)$ in d+Au collisions divided by $N(K^{*0})N(K^-)$ ratio in d+Au collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias Au+Au collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias Cu+Cu collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias p+p collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias Au+Au collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias Cu+Cu collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(K^{*0})/N(K^-)$ ratio in minimum bias p+p collisions as a function of $\sqrt{s_{NN}}.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio for Au+Au at $\sqrt{s_{NN}}$ = 62.4 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio for Cu+Cu at $\sqrt{s_{NN}}$ = 62.4 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio for Au+Au at $\sqrt{s_{NN}}$ = 200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio for Cu+Cu at $\sqrt{s_{NN}}$ = 200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $[N(\phi)/N(K^{*0})]$ in Au+Au collisions divided by $[N(\phi)/N(K^{*0})]$ ratio in p+p collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $[N(\phi)/N(K^{*0})]$ in Cu+Cu collisions divided by $[N(\phi)/N(K^{*0})]$ ratio in p+p collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $[N(\phi)/N(K^{*0})]$ in d+Au collisions divided by $[N(\phi)/N(K^{*0})]$ ratio in p+p collisions at $\sqrt{s_{NN}}$=200 GeV as a function of $⟨N_{part}⟩$

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias Au+Au collisions as a function of $\sqrt{s_{NN}}$.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias Cu+Cu collisions as a function of $\sqrt{s_{NN}}$.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias p+p collisions as a function of $\sqrt{s_{NN}}$.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias Au+Au collisions as a function of $\sqrt{s_{NN}}$.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias Cu+Cu collisions as a function of $\sqrt{s_{NN}}$.

Mid-rapidity $N(\phi)/N(K^{*0})$ ratio in minimum bias p+p collisions as a function of $\sqrt{s_{NN}}$.

The $K^{*0}$ $v_2$ (Run IV) as a function of $p_T$ in minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

The $K^{*0}$ $v_2$ (Run II) as a function of $p_T$ in minimum bias Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.

The $K^{*0}$ $R_{CP}$ as a function of $p_T$ in Au+Au collisions at 62.4 and 200 GeV compared to the $R_{CP}$ of $K^0_S$ and $\Lambda$ at 200 GeV.

The $K^{*0}$ $R_{CP}$ as a function of $p_T$ in Au+Au collisions at 62.4 and 200 GeV compared to the $R_{CP}$ of $K^0_S$ and $\Lambda$ at 200 GeV.

The $K^{*0}$ $R_{CP}$ as a function of $p_T$ in Au+Au collisions at 62.4 and 200 GeV compared to the $R_{CP}$ of $K^0_S$ and $\Lambda$ at 200 GeV.

The $K^{*0}$ ~$R_{CP}$~ as a function of $p_T$ in Au+Au collisions at 62.4 and 200 GeV compared to the $R_{CP}$ of $K^0_S$ and $\Lambda$ at 200 GeV.

Background-subtracted charge-independent (AAT ) correlated hadron pair density in 40-80% Au+Au collisions for 3<p(t)⊥<10 GeV/cand 1<p(a)⊥<3 GeV/c. The results are for near-side correlated hadrons within |∆φ1,2|<0.7, and corrected for the 3-particle ∆η-∆η acceptance. Statistical errors at (∆η1,∆η2)∼(0,0)are approximately 0.058 for Au+Au respectively..

Background-subtracted charge-independent (AAT ) correlated hadron pair density in 0-12% Au+Au collisions for 3<p(t)⊥<10 GeV/cand 1<p(a)⊥<3 GeV/c. The results are for near-side correlated hadrons within |∆φ1,2|<0.7, and corrected for the 3-particle ∆η-∆η acceptance. Statistical errors at (∆η1,∆η2)∼(0,0)are approximately 0.084 for Au+Au respectively..

The average correlated hadron pair density per trigger particle as a function of R for all charges in minimum 0-12% Au+Au collision. The average〈ˆP〉for AAT as a function of R = $\sqrt{∆η21+ ∆η22}$. The average density is peaked at R∼0 and decreases with R for all systems. In 0-12% Au+Au collisions, the average denstiy drops more slowly andbecomes approximately constant aboveR>1, indicatingthe presence of the ridge.

The average correlated hadron pair density per trigger particle as a function of R for all charges in minimum 40-80% Au+Au collision. The average〈ˆP〉for AAT as a function of R = $\sqrt{∆η21+ ∆η22}$. The average density is peaked at R∼0 and decreases with R for all systems. For 40-80% Au+Au collisions the average density at R>1 is consistent with zero, indicating no ridge contribution

The average correlated hadron pair density per trigger particle as a function of R for all charges in minimum d+Au collision. The average〈ˆP〉for AAT as a function of R = $\sqrt{∆η21+ ∆η22}$. The average density is peaked at R∼0 and decreases with R for all systems. For d+Au collisions the average density at R>1 is consistent with zero, indicating no ridge contribution

Radial dependence of average 3-particle correlation pair density for 0-12% Au+Au (like-sign triplets) data. The results are shown in Fig. 3(b) Indeed, no jet-like component is apparent in A^±A^±T^±.The A^±A^±T^∓ result contains both jet-like and ridge components.

Radial dependence of average 3-particle correlation pair density for 40-80% Au+Au (like-sign triplets) data. The contribution from other charge combinations, namely A^±A^∓ T^±, are simply the difference between AAT in Fig.3(a) and (A^±A^±T^± + A^±A^± T^∓) in Fig. 3(b). We found this to be equal to twice the A^±A^± T^∓contribution within errors.

Radial dependence of average 3-particle correlation pair density for d+Au (AAT) data. We expect the ridge contributions in the correlated pair density to be the same in all charge combinations. We verified this for large ∆η correlatedpair densities within our current statistics, as can be seen from Fig. 3(b). Therefore the total ridge particle pair density (ˆPrr) can be obtained as four times A^±A^±T^±. The remaining jet-like signal, the sum of jet-like correlated particle pairs (ˆPjj) and cross pairs of a jet-like and a ridge particle (ˆPjr), can then be obtained by subtracting the total ridge from AAT.

for same-sign associated particles (A^\pm A^\pm T^\pm and A^\pm A^\pm T^\mp) in 0-12% Au+Au collisions Systematic uncertainties are shown in the shaded boxes due to background normalization and in the solid curves due to flow.

The R dependence of the average〈ˆPrr〉and〈ˆPjj〉+〈ˆPjr〉in 0-12% Au+Au collisions.The ridge pair density is consistent with a constant 60.14±0.02 (χ2/ndf=5.8/7). Gaussian fits indicate a best fit value σ = 2.1 (χ2/ndf=4.8/6, solid curve) and σ >1.4 (dashed curve) with 84% confidence level. On the otherhand, the jet-like component is narrow with a Gaussianσ=0.34+0.13−0.09(χ2/ndf=0.8/6, dominated by statistical errors), comparing well to those from the correlated single hadron density.

The average correlated hadron pair density per trigger particle in 0-12% Au+Au collisions for the jet-like andridge components as a function of R. The solid curves are Gaussian fits. The dashed curve is a Gaussian fit with a fixed σ=1.4 to the ridge data. The systematic uncertainities on the ridge data are shown in shaded boxes due to background normalization and in open boxes due to flow.

The R dependence of the average in 0-12% Au+Au collisions.for the ridge as a function of ξ within R<1.4. The solid curves are Gaussian fits. To investigate possible structures in the ridge, we show in Fig. 4(b) the average ridge particle pair density as a function of ξ = arctan(∆η2/∆η1) within R<1.4. The data are consistent with a uniform distribution in ξ(χ2/ndf=1.7/7). This suggests that the ridge particles are uncorrelated in ∆η not only with the trigger particle but also between themselves. In other words,the ridge appears to be uniform in ∆η event-by-event.