Neutral Pion Production in pp Collisions at √s = 2.76 TeV at the LHC with the ALICE Detector using the Electromagnetic Calorimeter

Abstract

In this thesis the measurement of the neutral pion yield and its differential invariant cross section in pp collisions at √s = 2.76 TeV is presented. The π^0 s are measured in the two photon decay channel and photons are reconstructed via the energy deposit in the EMCal . To obtain the π^0 yield, the strategy is to extract the signal from the invariant mass distribution of photon pairs by subtracting the combinatorial background, which is calculated mainly via the mixed events technique. The measurement of π^0 spectrum reaches to 10 GeV, being limited by the statistic and energy deposit overlap in the EMCal. Finally, the measurement is compared to the spectra measured via the Photon Spectrometer (PHOS) and that from the Photon Conversion Method (PCM) [1]. All three independent measurements agree within ±10%, which is fully constistent with their individual sytematic and statiscal errors, and can thus be combined. The combined π^0 spectrum agrees with the NLO perturbative QCD prediction by M. Strattmann [2] and the charged pion measurement [3] at the same center-of-mass energy reasonably well.