Jet-Chemistry in Heavy Ion Collisions at RHIC

In this work the rst measurements of identi ed charged pions and (anti) protons for the jet-cone and ridge parts of di-hadron correlation functions with respect to high pT trigger are presented for Au+Au 200 GeV, 0-12 % most central events. The proton to pion ratio measured for the associated hadrons within the jet-cone is found signi cantly lower than that reported in the inclusive 200 GeV central Au+Au events. The observed proton to pion ration in the jet-cone is of the order of 0.2, and this is consistent with pQCD expectation for jet fragmentation. On the other hand, the proton to pion ration in the ridge part of the di-hadron correlation function shows enhancement of relative baryon to meson production, similar to that reported for inclusive events. The spectral shapes for the measured identi ed associated hadrons show similar trends: both pion and (anti)proton distributions in the ducial range for the jet-cone are signi cantly harder than corresponding inclusive measurements, while e ective spectral slopes measured for the ridge parts are similar to the respective pion and proton shapes in the inclusive events. These observations indicate that di erent production mechanisms are likely responsible for the hadron formation in the jet-cone and the ridge regions.