Transverse momentum spectra of unidentified charged particles in pp, p-Pb and Pb-Pb collisions with ALICE

To study the properties of matter created in p-Pb and Pb-Pb collisions, a common observable is the nuclear modification factor as function of the transverse momentum (p_T) of charged particles. The ALICE detector at the CERN-LHC has accumulated a wealth of data on pp, p-Pb and Pb-Pb collisions in the past years. Using a combined tracking approach based on information in the Inner Tracking System (ITS) and the Time Projection Chamber (TPC) ALICE is capable to measure the transverse momentum in a broad p_T range up to p_T=50 GeV/c in these collision systems. For the calculation of the nuclear modification factor, pp reference spectra are needed. In this talk, the extraction of the pp baseline spectra for p-Pb and Pb-Pb collisions for charged particles is discussed. The nuclear modification factor measured in Pb-Pb collisions is presented. Based on the same tracking approach, ALICE can measure the transverse momentum of charged particles down to p_T=150 MeV/c, which is crucial for the measurement of the average transverse momentum. A systematic study of the system-size and collision energy dependence of the average transverse momentum and its correlation to charged particle multiplicity is presented.