Neutral meson production and correlation with charged hadrons in pp and Pb-Pb collisions with the ALICE experiment at the LHC

Among the probes used to investigate the properties of the Quark-Gluon Plasma, the measurement of the energy loss of high-energy partons can be used to put constraints on energy-loss models and to ultimately access medium characteristics, such as the energy density or the temperature. The study of two-particle correlations allows us to obtain very different constraints compared to the nuclear modification factor. In particular, the correlation of charged hadrons with high energy π0 or direct photons is believed to give a measurement of the parton energy loss and insights into the medium-induced modification of the fragmentation process. High energy neutral pions are reconstructed using the ALICE electromagnetic calorimeters EMCal and PHOS, and the charged particles are detected by the main tracking detectors ITS and TPC. In these proceedings, the measurement of neutral mesons at s=2.76TeV in pp collisions are presented, as well as the measurements of azimuthal π0 -hadron correlations in pp and Pb-Pb collisions at s=2.76TeV , and the extracted per-trigger yield modification factor ( IAA ). Comparisons with theoretical model calculations are also added.