To estimate the fake J/&psi background we look at the sidebands of the J/&psi mass distribution and match a third muon to events that fall into the sideband regions. Figure 13 shows the J/&psi mass distribution for events matched with a third muon for both the signal and sideband regions. Using the sideband regions we estimate the Fake J/&psi background to be 19.0 ± 3.0 events for the 4.0-6.0 GeV/c2 mass region. |
Figure 13: Left: J/&psi mass distribution for signal and sideband events matched with third muon. Right: J/&psi mass distribution for fake J/&psi events. |
We also must account for double counting of events that contain both a fake J/&psi and a fake muon. We do this by appling our fake muon rates to J/&psi sideband events matched with a third track. We estimate this double counting to be 2.0 ± 0.5 events in the 4.0-6.0 GeV/c2 mass region. |