HERA-b: c and b production

HERA-B is a fixed-target multi-particle spectrometer experiment at the 920 GeV HERA proton beam at DESY. Approximately 150 million events were recorded with a dilepton trigger during the 2002/2003 HERA run. About 300,000 leptonic J/ l + l -decays (170,000 in the + - channel and 130,000 in the e + e -channel) have been reconstructed in this data sample. In addition, a huge sample of 220 milion minimum biased triggered events were recorded, allowing an independent measurement of the J/ production cross section. The dilepton triggered samples allow for the first time the study of charmonium production in the negative Feynman-x (x F ) region, and will provide an important input for testing the charmonium production mechanism. Results will be presented on the nuclear dependence of charmonium production, on J/, c and production and on their differential distributions. Furthermore, the first measurement of the nuclear suppression of charmonium production in the negative x F region will be presented. In the field of b-quark physics, the available statistics allows a precise measurement of the inclusive b b and of the production cross sections. The b b production has been tagged via inclusive b-quark decays into a J/, by exploiting the longitudinal separation of J/ l + l -decay vertices from the primary proton-nucleus interaction. The production cross sections, as measured directly in dimuon and dielectron decay channels, will also be presented. All results presented in this proceedings are preliminary.