D*+ meson measurement in proton-proton collisions at 8 TeV with the ALICE detector
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The D* invariant production cross-section in proton proton collisions at 8 TeV at the Large Hadron Collider is reported in this thesis. D* mesons are reconstructed in the hadronic channel D* -> D0 pi+ -> K- pi- pi+ by means of the invariant mass analysis method. About 100M minimum bias triggered events are analysed and the D* meson is successfully reconstructed in the pT range 1-24 GeV/c. The acceptance times efficiency correction is extracted from the Monte Carlo production LHC15l2a2. The pT-differential cross sections are compared with FONLL predictions. The overall production is described within the theoretical error band by Fixed Order plus Next-to-Leading Logarithm (FONLL) calculations although the data tends to be higher than the central value of the FONLL predictions. The ratio of the cross-sections at 8 and 7 TeV as well as the ratio of the cross-section D* and D+ is also computed and compared with FONLL predictions. In addition to minimum bias data, EMCal triggered data is analyzed to increase the cross-section pT range. A forced and a minimum bias Monte Carlo (MC) production are used to compute a trigger bias. The forced MC has enough statistics but does not reproduce the triggering probability properly. The trigger bias from the minimum bias MC corrects the EMCal data to reproduce the MB cross-section reasonably well but 20% lower on average and with low statistics. A MC production which increases the D meson statistics without influencing the trigger bias is needed to successfully extend the pT range of the cross-section. In addition, dedicated studies on which particle triggers are needed to account for the 20% difference. The results of this work were approved by the ALICE Collaboration as official and will be presented at the Hard Probes conference.