| dc.description.abstract | Theories predict that shortly after the big bang the universe was filled with a phase of matter known as the quark-gluon plasma. The quark-gluon plasma is predicted by Quantum Chromodynamics, and only exists for very high densities and/or temperatures. Nowadays, these conditions can be reached in particle colliders such as the Large Hadron Collider at CERN. Experiments with the ALICE detector focus on studying the properties of this quark-gluon plasma. One of the ways to study the quark-gluon plasma is by looking at the difference of the properties of B mesons that travel through a quark-gluon plasma and those who do not travel trough it. A quark-gluon plasma is created at high energy Pb-Pb collisions, but not in p-p collisions. For this thesis, a Monte-Carlo data set of p-p collisions at 7 TeV is analyzed. We focus on the D*+ meson that is created in these interactions. The D*+ mesons can be produced by a charm quark (prompt) or by the decay of a B meson (feed-down), which itself is produced by a beauty quark. The purpose of this study is to separate these two different decay channels. In order to do this, we make use of the fact that feed-down mesons are displaced (i.e. they are not created at the collision point). By reconstructing the D*+ mesons we can find their impact parameter, which is expected to be higher for feed-down mesons. In this study, this has been verified, and cuts on impact parameter have been applied. The cuts have been applied on the impact parameter of the pions and kaons, which are decay products of the D*+ meson. The study has been performed for different pT bins of the D*+ meson. By applying the cuts on impact parameter, it turns out that we are able to increase the ratio of feed-down D*+ mesons up to 100%. For higher pT of the D*+ meson, the cuts are more efficient. By applying these cuts on real data, we will be able to study the B meson in p-p collisions. A small outlook is given in this thesis, where expectations for the cuts in Pb-Pb collisions in the new detector setup of ALICE are discussed. | |
