Removal of Anisotropic Background from Neutral Pion and Tagged Direct Photon–Hadron Correlations of Au+Au 200 GeV Collisions
A reaction plane dependent event mixing technique is developed to remove the collective background from two particle correlation measurements in heavy ion collisions. The method eliminates the need for any external flow measurements and is well suited for studying the path length dependence of particle production in quark-gluon plasma. Central to mid-central, as well as in vs out-of-plane, per neutral pion trigger integrated away-side hadron yield comparisons are made. Results suggest a significant path length dependent partonic energy loss in the medium. A tagging method is also introduced to measure the direct photon yield for various collision criteria. Direct photon – hadron yields are measured. A comparison of central to mid-central yields reveals a significant suppression of the away-side hadrons in higher multiplicity events. The reaction plane dependence of the associated away-side yield is explored.
Nuclear, quark-gluon plasma, high energy, QCD, photon, pion, heavy ion
City University of New York - Graduate Center
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The Graduate School and University Center of The City University of New York