Heavy quark production in 920 GeV proton-nucleus collisions

HERA-B is a fixed-target multi-particle spectrometer experiment at the 920 GeV HERA proton beam at DESY The collected data sample from the 2002/2003 HERA run includes 200 million interactions recorded with a minimum bias trigger and about 300,000 J/psi decays recorded with a dilepton trigger. These data samples are being analyzed to extract production cross sections for J/psi, gamma, and charmed mesons as well as the total b-quark production cross section. Additionally, aspects of charmonium production including the chi(c) to J/psi cross section ratio, the psi(2S) / J/psi cross section ratio, and the x(F), transverse momentum and atomic number dependence of the J/psi cross section in the target hemisphere are under investigation. Preliminary results on these topics are presented.