Preliminary measurement of Transversity at COMPASS experiment

In the COMPASS physics program a particular attention is devoted to the spin dependent Parton Distribution Functions. The observables related to Transversity are the subject of this work. As a first hint for these measurements, the data collected during year 2002 run have been analyzed. This sample, taken with a transverse polarized deuteron target, consists of about 15 days of smooth data taking. In this thesis, after a phenomenological introduction to the physics case, a detailed description of the COMPASS spectrometer is given, pointing the attention to the RICH detector and its performance. The analysis algorithms are fully described. Preliminary results on Transversity, obtained via the so-called Collins effect, are shown.