Summary of Systematic Uncertainties

Our primary source of systematic uncertainty in the background estimate comes from the uncertainties in the fractional cross sections for FC, FE and GS in the Pythia sample that we use to estimate the bb background. This leads to an uncertainty of 5.7 events. The fake muon estimate contains systematic uncertainties from two major sources: the estimate of the proton fraction in the third track sample and the affect of decay-in-flight events that move out of the D⁰ peak on the fake muon rates. These sources account for a systematic error of 2.1 events in the fake muon estimate. The fake J/&Psi background estimate's error is dominated by the statistical uncertianty of the small sample of sideband J/&Psi events that get matched with a muon.

The sources of systematic uncertainty for our relative cross-section times branching ratio estimate are contained within the relative efficiency &epsilon_rel for reconstructing B^±->J/&psi K^± and B_c->J/&psi &mu. Table 5 summarizes the uncertainties for &epsilon_rel with the largest source coming from the uncertainty in the spectrum of B_c events. Another large source of uncertainty in &epsilon_rel is the B_c lifetime which was measured in Run I to be 0.46^+0.18 _-0.16 ps².