Exploration of jet energy loss via direct γ-charged particle azimuthal correlation measurements

The multiplicities of charged particles azimuthally associated with direct photons and π0 have been measured for Au+Au, p+p, and d+Au collisions at in the STAR experiment. Charged particles with transverse momentum for p+p and d+Au, and for Au+Au and pseudorapidity |η|⩽1.5 in coincidence with direct photons and π0 of high transverse momentum at |η|⩽0.9 have been used for this analysis. Within the considered range of kinematics, the observed suppressions of the associated yields per direct γ in central Au+Au relative to p+p and d+Au are similar and constant with direct photon fractional energy . The measured suppressions of the associated yields with direct γ are comparable to those with π0. The data are compared to theoretical predictions.