Measurements of D-meson production with ALICE

Heavy quarks (charm and beauty) are produced in hard parton scattering processes in the initial stages of hadronic collisions. The study of their production can give us different information in each type of collisions. In pp collisions at the LHC it provides a test of perturbative QCD calculations at the highest collision energy. In p-Pb collisions it allows one to characterise the nuclear modification of the parton distribution functions and the k T -broadening effect due to soft scatterings of the partons in the incoming nuclei. Moreover, it provides insight into possible final state effects that could occur in p-Pb collisions, like energy loss of heavy quarks in the cold nuclear matter and their collective behaviour. In Pb-Pb collisions, heavy-flavour production can be used to study the properties of the high energy-density and strongly-interacting medium created in heavy-ion collisions. Passing through all the phases of the system evolution, heavy quarks lose energy via gluon radiation and elastic collisions in the medium. Therefore, the study of their production can be used to test parton energy-loss models.