Azimuthally Sensitive Hanbury Brown–Twiss Interferometry measured with the ALICE Experiment

Bose–Einstein correlations of identical pions emitted in high-energy particle collisions provide information about the size of the source region in space-time. If analyzed via HBT Interferometry in several directions with respect to the reaction plane, the shape of the source can be extracted. Hence, HBT Interferometry provides an excellent tool to probe the characteristics of the quark-gluon plasma possibly created in high-energy heavy-ion collisions. This thesis introduces the main theoretical concepts of particle physics, the quark-gluon plasma and the technique of HBT interferometry. The ALICE experiment at the CERN Large Hadron Collider (LHC) is explained and the first azimuthally integrated results measured in Pb–Pb collisions at sqrt(s_NN) = 2.76TeV with ALICE are presented. A detailed two-track resolution study leading to a global pair cut for HBT analyses has been performed, and a framework for the event plane determination has been developed. The results from azimuthally sensitive HBT interferometry are compared to theoretical models and previous measurements at lower energies. Oscillations of the transverse radii in dependence on the pair emission angle are observed, consistent with a source that is extended out-of-plane.