Isolated Photon-Hadron Correlations in pp and p--Pb Collisions at $\sqrt{s_\mathrm{NN}}$= 5.02 TeV Measured with the ALICE Detector

The measurement of isolated photon-tagged correlations of jets and jet fragments is a promising channel for the study of partonic energy loss in heavy-ion collisions. Photons are measured in the ALICE EMCal. We use a combination electromagnetic shower-shape information and isolation criteria obtained with the ALICE ITS to reduce the large background from meson decays and fragmentation photons. We present isolated photon-hadron correlations and yields of charged hadrons in $\sqrt{s_{\rm NN}} = $ 5.02 TeV pp and p—Pb collisions in an unexplored kinematic range: [12-40] GeV/$c$ for the photon $p_{\rm T}$ and [0.7-10] GeV/$c$ for the charged track $p_{\rm T}$. We report the first measurement of photon-tagged parton fragmentation in p--Pb at the LHC. We show the ratio of fragmentation measurements in pp and p--Pb is consistent with unity, constraining the impact of cold nuclear matter effects on parton fragmentation.