A statistical combination method for the search of supersymmetry

Despite its success, the Standard Model of particle physics, is however not able to consistently explainmany subatomic phenomena. For this reason some new theories are being developed to complete andallow to go beyond the Standard Model. One of those theories is that of Supersymmetry, whichvalidity has not been not completely verified. In order to be sensitive to such rare processes, as theSUSY ones, complex statistical methods are to be used. In this thesis we perform a statisticalcombination of two searches for SUSY particles. In particular we will search for the pair production ofcharginos and neutralinos.To accomplish this task, is considered a statistical method aimed to determine, at which combinationsof the neutralinos’ masses the existence of those same particles can be excluded. The statisticalmethod consists in building a statistical model starting from an observation x= (n,a), which dependsamong other things from the mass values of the searched particles, then in using the hypothesis testingmethod on the models obtained from each mass combination. This way it’s possible to statisticallyestablish whether the hypothesis of the presence of a new signal over the background signal, i.e. of thesearched particles has to be excluded or not.This method is applied in two known cases, one in which the W/Z bosons involved in the studiedprocess are real and the other in which they are virtual, and in a third new case where the data of theother two is combined in order to lead a new analysis that allows a greater sensitivity in the search ofthe possible neutralino’s masses