| The objective of this thesis is to develop tools for interpretation of the upcoming particle physics experiments.; We implement and test Optimal Jet Finder (OJF), a jet finding algorithm that is based on the global energy flow in the event. OJF is infrared and collinear safe and resolves overlapping jets dynamically. The shapes of jets are determined dynamically and are not geometrical cones. However, they are more regular than those resulting from k⊥, which should facilitate detector calibration of OJF. We compare the statistical uncertainties of the W-boson mass when using three different jet finding algorithms: k⊥ . JADE, and OJF. We find that OJF gives the same accuracy as k ⊥ but is faster than k⊥ if a large number of calorimeter cells is analyzed. We present the details of FORTRAN 77 and object-oriented C++ implementations of OJF.; We calculate the rate of the lepton flavour violating mu → e + gamma decay in a particular Grand Unification SO(10) model by Albright and Barr. We assume the Constrained Minimal Supersymmetric Standard Model framework. We interpret the results in view of the recent cosmological observations from Wilkinson Microwave Anisotropy Probe. We find that the SO(10) model is consistent with the experimental limits on the mu → e + gamma branching ratio over a large volume of the supersymmetric parameter space. However, if the branching ratio is further constrained by the MEG experiment, carried out in the Paul Scherrer Institute, below 10 -13, the available volume of the parameter space will be significantly reduced.; We calculate the QED suppression of the rate of the lepton flavour violating mu → e + gamma decay. The result, does not depend on the details of the mechanism that, is responsible for the lepton flavour violation, except for the mass scale that enters the final expression. If this mass scale is between 100 and 1000 GeV, the numerical value of the decrease in the decay rate is between 12% and 17%. If the rare muon decay is observed in the MEG experiment, our result will enhance the precision with which the parameters of the new physics models responsible for this decay can be extracted. |
