D*+ production in 7 TeV proton-proton and 5.02 TeV proton-lead collisions with ALICE

Abstract

Sections~1-4 cover the theory needed to address this topic. The reader will find a brief introduction into Quantum Chromo-Dynamics and an interesting consequence of this theory: asymptotic freedom, which in turn leads to deconfinement. Next, the Quark Gluon Plasma is discussed. Finally, the D$^*$ meson, the subject of this thesis, is studied by looking at its decay modes, how it is reconstructed and the track- and topological cuts needed for the yield extraction.\\ Section~5 focuses on the extraction of the D$^*$ meson yield in proton-lead collisions at $\sqrt{s}=5.02$ TeV, the first step in the calculation of the nuclear modification factor in proton-lead interactions. Firstly, the best topological cuts per $p_{\text{T}}$ bin are found. Particular attention is given to the lower $p_{\text{T}}$ bin $[1,2]$ GeV$/c$, where the signal extraction is more challenging due to a large combinatorial background due to random pairs. Next, we calculate the yield with a function which we fit to the data, using different fitting parameters. We also use a bin counting method. Finally, the systematic uncertainty is derived from this.\\ Section~6 looks at the feasibility of using $e-D^*$ correlations to study charm to beauty production in the beginning stages of the Quark Gluon Plasma. First, the correlation method is explained and afterwards a correlation is done for a MonteCarlo generated enhanced- and minimum bias sample for proton-proton collisions at $7$ TeV. Finally, the process types gluon splitting, pair creation and flavour excitation are studied with this correlation method. The discussion then focusses on the feasibility of applying this method in order to determine the relative beauty fraction as well as the separation of $b\bar{b}$ and $c\bar{c}$ pairs.\\ Finally, in section~7 a conclusion is made. After this section the reader also finds the appendices.