Investigation of heavy-quark production in proton-nucleus collisions with the HERA-B detector

Results obtained with the aid of the HERA-B detector, which operated at an internal target in a 920-GeV proton beam of the HERA storage ring at DESY (Hamburg, Germany), are discussed. About 164 million dilepton-triggered and 210 million minimum-bias events were collected over the data-taking time. These vast statistics made it possible to study in detail charmonium production in proton—nucleus collisions. Inclusive cross sections for open-charm, open-beauty, and ?-meson production weremeasured. The results are compared with the respective predictions of theoretical models.