We report the first three-particle coincidence measurement in pseudorapidity ($\Delta \eta$) between a high transverse momentum ($p_{\perp }$) trigger particle and two lower $p_{\perp }$ associated particles within azimuth $|\Delta \varphi |<0.7$ in $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ $d+\mathrm{Au}$ and $\mathrm{Au}+\mathrm{Au}$ collisions. Charge ordering properties are exploited to separate the jetlike component and the ridge (long range $\Delta \eta$ correlation). The results indicate that the correlation of ridge particles are uniform not only with respect to the trigger particle but also between themselves event by event in our measured $\Delta \eta$. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jetlike component.

• Received 8 February 2010

DOI:https://doi.org/10.1103/PhysRevLett.105.022301