The correlation function C, C is plotted in units of (GeV/c)$^2$ and the relative azimuthal angle ∆φ in radians for 30-40% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. Relative statistical errors range from 0.8% in peripheral collisions to 0.9% in the most central collisions at the peak of the distribution.

The correlation function C, C is plotted in units of (GeV/c)$^2$ and the relative azimuthal angle ∆φ in radians for 0-5% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV..Relative statistical errors range from 0.8% in peripheral collisions to 0.9% in the most central collisions at the peak of the distribution.

The correlation function C, C is plotted in units of (GeV/c)$^2$ and the relative azimuthal angle ∆φ in radians for 0-5% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV..Relative statistical errors range from 0.8% in peripheral collisions to 0.9% in the most central collisions at the peak of the distribution.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 70-80% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The correlation function C is plottedin units of (GeV/c)$^2$.The correlation function C is plotted in units of (GeV/c)$^2$. The solid line shows the fit obtained with Eq.2. The dotted line corresponds to the baseline, b, obtained in the fit and shaded band shows uncertainty in determining b.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 70-80% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The correlation function C is plottedin units of (GeV/c)$^2$.The correlation function C is plotted in units of (GeV/c)$^2$. The solid line shows the fit obtained with Eq.2. The dotted line corresponds to the baseline, b, obtained in the fit and shaded band shows uncertainty in determining b.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 30-40% centrality. Statistical errors at(\Deltaeta_1,Deltaeta_2~(0,0) are approximately 0.084 for Au+Au. The correlation function C is plotted in units of (GeV/c)$^2$. The dotted line corresponds to the baseline,b, obtained in the fit and shaded band shows uncertainty in determining b.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 30-40% centrality. Statistical errors at(\Deltaeta_1,Deltaeta_2~(0,0) are approximately 0.084 for Au+Au. The correlation function C is plotted in units of (GeV/c)$^2$. The dotted line corresponds to the baseline,b, obtained in the fit and shaded band shows uncertainty in determining b.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 0-5% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The correlation functionCis plotted in units of (GeV/c)$^2$. The correlation function C is plotted in units of (GeV/c)$^2$. The solid line shows the fit obtained with Eq.2. The dotted line corresponds to the baseline,b, obtained in the fit and shaded band shows uncertainty in determining b.

Projection of the correlation function C, for|∆φ|<1.0 radians on the ∆η axis for 0-5% centrality in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The correlation functionCis plotted in units of (GeV/c)$^2$. The correlation function C is plotted in units of (GeV/c)$^2$. The solid line shows the fit obtained with Eq.2. The dotted line corresponds to the baseline,b, obtained in the fit and shaded band shows uncertainty in determining b.

RMS as function of the number of participating nucleons for the correlation function C, for nine centrality classes in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The dotted line represents a lower limit estimate of the RMS explained in the text and the shaded band represents systematic uncertainties on the RMS.

RMS as function of the number of participating nucleons for the correlation function C, for nine centrality classes in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The dotted line represents a lower limit estimate of the RMS explained in the text and the shaded band represents systematic uncertainties on the RMS.

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.