Commissioning of the Silicon Pixel Detector of ALICE and perspectives for beauty production at LHC

The activities carried out within the present work were aimed at the preparation for heavy quarks measurements, thus including the construction and commissioning of the SPD. More in detail, they can be summarised in the following: • Assembly of the silicon pixel sensors on the carbon fibre support. Given its role as a precision tracker, the assembly of the SPD requires the use of specific procedures to ensure a high degree of accuracy. • Tuning and maintenance of the cooling system of the SPD. The SPD power dissipation is of about 1.5 kW. This means that, without cooling, the temperature of the sensors would rise at about 1°C/s. The cooling system is thus of vital importance for the operation of the detector. • Development of a set of tools for the monitoring of the alignment procedures of the ITS and, in particular of the SPD. The misalignment of the detector must be accounted for in the software description of the geometry in order to optimize the spatial resolution. The matching of the geometry with the data is done using software procedures. A dedicated set of tools has been developed to control the results of this phase and to evaluate the resolution of the detector. • Study of the possibility of using semi-electronic decays of beauty particles for the investigation of the QGP, with an emphasis on the specific issues of the first LHC runs (electron PID and misalignment). The simulation studies reported here are devoted to assess ALICE performance in measuring the nuclear modification factor and the elliptic flow of electrons from beauty decays. Moreover, using previous studies on the charm production measurement, it has been possible to estimate the sensitivity to the mass dependence of the partonic energy loss.