Three-particle coincidence of the long range pseudorapidity correlation in high energy nucleus-nucleus collisions

The collaboration
Phys.Rev.Lett. 105 (2010) 022301, 2010.

Abstract (data abstract)
We report the first three-particle coincidence measurement in pseudorapidity (∆η) between a high transverse momentum (p⊥) trigger particle and two lower p⊥ associated particles within azimuth |∆φ|<0.7 in $\sqrt{s_{NN}}$= 200 GeV d+Au and Au+Au collisions. Charge ordering properties are exploited to separate the jet-like component and the ridge (long-range ∆η correlation). The results indicate that the particles from the ridge are uncorrelated in ∆η not only with the trigger particle but also between themselves event-by-event. In addition, the production of the ridge appears to be uncorrelated to the presence of the narrow jet-like component.