Low Mass Dimuon Production in Proton-Nucleus Collisions at 400 GeV at the CERN-SPS

During the June 2002 run the fixed-target experiment NA60 collected around 600000 dimuon triggers in proton-nucleus collisions at 400 GeV. The target system consisted of Beryllium, Indium and Lead targets, of roughly the same interaction length, simultaneously exposed to the beam. This specific setup allowed to study the nuclear dependence of the production cross-section of the $\omega$ and $\phi$ resonances. The elementary pp production cross-sections at 400 GeV for the $\rho$, $\omega$ and $\phi$ mesons are also presented. This thesis presents a general understanding of the collected dimuon mass spectra in terms of known sources. By using the $\eta$-Dalitz decay, dominating the 0.2--0.45 GeV mass range, an attempt was made to, furthermore, extract the $\eta$ production cross-section and its nuclear dependence. The results are discussed in the framework of previous measurements, mostly obtained in different decay channels, performed by NA27, HELIOS-1 and CERES-TAPS. These data were collected with the newly designed Silicon micro-strip tracking telescope of NA60, whose prototyping, testing, assembling and operation was also part of the present thesis. The raw data analysis of this analogue read-out detector is also presented, together with the detector's performance during this period of data taking.