Direct photon-hadron correlations measured with the PHENIX detector

Photon tagged jets are an excellent probe of the hot dense matter created in heavy ion collisions at RHIC. Since photons interact weakly and are not modified by the strongly coupled medium, the measured photon momentum approximately balances that of the away-side parton. Therefore, the modification of the fragmentation function can be obtained by comparing the spectra of the away-side yields in direct photon-hadron correlations in Au+Au collisions to those in p+p. Direct photon-hadron correlations are measured with the PHENIX detector in p+p and Au+Au collisions at at RHIC. We employ a statistical subtraction method to remove the contribution of decay photons from the inclusive photon-hadron correlations. For the p+p analysis, we developed event by event techniques to improve the systematic uncertainty in the baseline measurement. Compared to previous measurements, this Au+Au result extends to higher ξ (lower zT) where a medium-induced modification of jet fragmentation is observed.