Measurement of neutral mesons in pp and Pb–Pb collisions at mid-rapidity with ALICE

International audienceOne of the key signatures of the Quark-Gluon Plasma (QGP), is the modification of hadron transverse momentum differential cross-sections in heavy-ion collisions (HIC) as compared to proton-proton (pp) collisions. Suppression of hadron production at high transverse momenta ( pT ) in HIC has been explained by the energy loss of the partons produced in the hard scattering processes which traverse the deconfined quantum chromodynamic (QCD) matter. The dependence of the observed suppression on the pT of the measured hadron towards higher pT is an important input for the theoretical understanding of jet quenching effects in the QGP and the nature of the energy loss. The ALICE experiment at the Large Hadron Collider (LHC) performs measurements of neutral meson inclusive spectra at mid-rapidity in a wide pT range in pp , p -Pb and Pb-Pb collisions. Neutral mesons ( π0,η,ω ) are reconstructed via complementary methods, using the ALICE electromagnetic calorimeters, PHOS and EMCal, and by the central tracking system, identifying photons converted into e+e− pairs in the material of the inner barrel detectors (TPC and ITS)