Optimierung der Berechnung des Neutrinoimpulses für Polarisationsstudien

Abstract

WZ-scattering processes are considered. For polarization studies of the W boson the momentum of the neutrino has to be calculated in order to completely reconstruct the W boson. Neutrinos cannot be detected in common experimental setups in particle colliders, such as the ATLAS detector employed at the LHC. As they only interact via the weak force, their momentum can only be deduced from conservation laws. They lead to a quadratic equation, which usually has two solutions, one of which has to be selected. This thesis deals amongst other things with methods to select a solution. Simulations of the ATLAS detector are used to check the calculation formulas. For some events the solutions are complex numbers; but it turns out that in these cases it is sufficient to use only the real part of the solution. For the events with a real solution the minimization of the neutrino momentum or of the invariant mass of W+Z are good criteria to select the right solution