Isolated photon-hadron correlations in proton-proton collisions at √s=7 TeV with the ALICE experiment

摘要

At high p_T, direct photons produced in Compton and annihilation QCD leading order processes are associated to a jet in the opposite direction. Such processes are tagged experimentally by identifying leading isolated photons and their correlated associated hadrons in the opposite azimuthal direction. The jet fragmentation can be estimated from the hadrons and the photon via the imbalance parameter χE=-p→Th{dot operator}p→Tγ/|p→Th|2. We present the results extracted from gamma-hadron correlations measured by the ALICE experiment in pp collisions at s=7 TeV. Direct photons are first identified using isolated criteria. Then, the remaining contamination from neutral mesons decay photons is subtracted statistically to extract the χ_E distributions of isolated photon-hadron and isolated π~0-hadron correlations.