Since we are searching for Bc in a semi-leptonic decay channel, we are unable to reconstruct a sharp mass peak, and it is therefore important to accurately estimate background J/&psi+&mu events. There are three sources of background events in our sample: fake muon events where a real J/&psi is matched with a track that fakes a muon (usually by decaying-in-flight or punching through to the muon chamber), bb events where the J/&psi& comes from one b quark while the muon comes from another, and fake J/&psi events where the J/&psi background events are matched with third muons. We summarize our estimates of these backgrounds in the following sections. |