Charm and beauty production at LHC

We define here the present ALICE baseline for what concerns the heavy flavour production cross sections at LHC and the kinematical distributions of the heavy quark pairs. We start by qualitatively assessing the Bjorken x regimes accessible with charm and beauty measurements at LHC with ALICE (Section 1). In Section 2 we report the most recent results (and the uncertainties) of the next-to-leading order (NLO) pQCD calculations for the cross sections in pp collisions at LHC energies. These results are extrapolated to Pb-Pb collisions in Section 3.1 and to p-Pb collisions in Section 3.2, taking into account nuclear shadowing and parton intrinsic transverse momentum broadening. Heavy quark kinematics as given by the NLO pQCD calculation are reported in Section 4. We tuned the PYTHIA event generator in order to reproduce such results for what concerns the c and b quarks transverse momentum distributions (Section 5). Finally, we report the yields and transverse momentum distributions for D and B mesons (section 6).