Studying the Jet Medium Interaction by Two Particle △η-△Φ Correlations

摘要

We present two dimensional △η-△Φ inclusive photon-charged hadron correlations measured by the PHENIX experiment. Jet-like correlations are modified in central Au+Au compared to p+p, in both the trigger jet and opposing jet. The trigger jet is elongated in pseudo-rapidity (the "ridge"), while the opposing jet shows a double peak structure (" head" and "shoulder"). We decompose the structures by fitting the △η and △Φ correlations to disentangle contributions from the medium and the punch-through and trigger jets. The ridge exists for associated particle p_T below 3 GeV/c; it is broad in rapidity and narrow in △Φ. The away side correlated particle yield is enhanced in central collisions. The yield of the ridge closely resembles the shoulder in the centrality dependence of particle yield and spectra.