Neutral Pion Production in p-Pb Collisions at √s^NN = 5.02 TeV with ALICE PHOS at the LHC

Abstract

In this thesis, the neutral mesons measurement with ALICE PHOS at the LHC is presented. Depending on the technical design of PHOS and its momentum reach, the strategies of the neutral mesons extraction by invariant mass analysis are studied. The main reason is due to the detector granularity. Clusters start to merge and maybe misidentified as single cluster in high multiplicity environment, as well as for high \pT π^0. Cluster unfolding algorithm and shower shape parameters allow us to separate γ and π^0 at high \pT. From current statistics with p-Pb collisions at √s^NN = 5.02 T eV , ∼ 90 million min-bias events are analyzed. By using the invariant mass analysis, π^0 spectrum is extracted to a \pT range of 25 GeV/c with PHOS. For the corrections of the raw spectrum, we take into account the geometrical acceptance and the reconstruction efficiency together by official DPMJET simulations. The final π^0 invariant yield are obtained with good matching with other three individual analysis.