Effetti sistematici sulla misura di $\Re (\epsilon^{'} / \epsilon)$ nell'esperimento NA48 al CERN: Efficienze di trigger e correzioni per accidentali

The discovery of CP violation in 1964 in the neutral kaon system opened a new frontier in particle physics. To the present time the only evidence for CP violation comes from K0 decays. Despite many theoretical and experimental efforts, the mechanism underlying CP violation is not completely understood. A clear observation of direct CP violation in the weak decay amplitude would rule out superweak models, providing a support for the Standard Model. The NA48 experiment, at CERN SPS, aims to search for direct CP violation through the measurement of Re(ε/ε) to 2×10−4. In order to achieve this precision, the experiment foresees to collect 5 million of $K_{L} \rightarrow \pi^{0}\pi^{0}$ within three years of data taking at high beam intensity, with a carefully designed architecture. In this thesis, after a recall of theory, a detailed description of the NA48 detector is given, pointing out the measurement strategy. A full chapter is dedicated to the innovative NA48 trigger system, a fully pipelined and dead time free system able to work at very high rate, which I contribute to develop. My analysis work has been devoted to the study of some systematic effects on the 97 data sample, in order to compute the relative corrections on Re(ε/ε). In particular, I studied in detail the two simultaneous beams effective correlation, the accidental activity correction and the charged and neutral trigger efficiency correction.