Figure 2
Fig. 2. Results from STAR on high-pT charged-particle angular correlations, showing the angular separation between a high-pT trigger particle and a lower pT probe. The solid line is from proton-proton collisions, showing near-side (same jet, Δφ ~0) and away-side (back-to-back jets, Δφ ~π). The squares represent the correlations in gold-gold collisions, where the trigger particles are aligned in-plane (see figure 1), and the diamonds represent particles aligned out-of-plane. Greater dissipation is observed out-of-plane, where the path length is longer.