Direct photon-hadron and Di-hadron correlations measured in PHENIX

We review results of PHENIX two-particle correlations for both di-hadrons and direct photon hadron pairs. These measurements can reveal details of QGP induced jet energy loss in heavy ion collisions. The spectra of per-trigger yields on the awayside from trigger photons in the photon-hadron correlations or fragmentation function for direct photons of greater than 5 GeV/c in transverse momentum appear to show some modification compared to the same measurement in p+p collisions, including a suppression at high z (> ~0.4), and much less suppression, possibly even enhancement at low z. A framework for calculating parton or jet level observables from the PHENIX 2-particle yields results that can be compared to recent LHC jet reconstruction observables. Under certain assumptions, one of these observables, the mean fractional energy loss, appears to be larger for lower jet energies (~10 GeV) that the PHENIX data is sensitive to, than for much higher energy jets (~100 GeV) at the LHC. However the current PHENIX di-hadron measurements for this comparison which may have inherent biases need to be followed up by higher statistics direct photon-hadron measurements before definite statements could be made.