We present the results of the two-particle $\Delta\phi$ correlation between high $p_T$ $\pi^0$ and charged hadrons in Cu+Cu collisions at $\sqrt{ s_{ NN}} = 200$ GeV. Clear away-side jet signals are seen in central Cu+Cu collisions at all associated hadron $p_T$, albeit suppressed by factor of 2 above 2 GeV/$c$. This level is similar to the suppression seen for inclusive hadrons at high $p_T$ ($>7$ GeV/$c$). However, this agreement is argued to be the result of a cancellation between a flatter away-side parton spectra due to the requirement of high $p_T$ triggers and a bigger energy loss due to a longer path length traversed by the away-side jet.
Categories: nucl-ex