Low pT Charm Meson Production at CDF II

I report on the differential production cross-section measurements of D mesons (D0 and D±) extended to low transverse momentum; I also show the first D0 signal ever observed in the sample collected at √s = 900 GeV. This measurement probes a region where perturbative QCD (pQCD) models are not able to describe the heavy-quark production because of the running of the strong coupling constant, αS. The data samples collected at two different center of mass energies, 1.96 TeV and 900 GeV, also give the opportunity to assess the energy dependence of the production cross section. The CDF II experiment can still give us distinguishing results, complementary to B-factories and LHC, thanks to the uniqueness of the combination of energies and collision initial state (pp̄), that are likely to remain the only ones of this kind for several years