Physics performance with the ALICE silicon tracker

The detailed characterization of the quark gluon plasma (QGP) produced in heavy-ion collisions is the main goal of the ALICE experiment at the CERN LHC . The analysis of heavy quarks via the decays of the corresponding short-lived hadrons is among the prominent measurements to address the properties of QGP . To efficiently reconstruct these decays, the ALICE apparatus comprises a precise Inner Tracking System (ITS) made out of six layers of silicon detectors based on three different technologies, namely two layers of pixels, two of drifts and two of double-sided microstrip, listed in the order they are crossed by particles produced in the beam collision. In this paper, the contribution of the ITS to some of the main physics measurements that have been accomplished with proton and lead beams by the ALICE experiment will be discussed.