Bob has more plots on tracking efficiency issues. See last week's plots and the week before's.
The left-hand plots are the dimuon masses as described in previous weeks, with a background fit (exponential against gaussian, χ squared 15/19 for the top, 20/21 for the bottom). He looked at the wings for the eta distribution, and used the Z fraction to subtract off the contribution from the background. The third column of plots is the η distribution from events where the COT track was found, and the fourth is the sum of the subtracted plot (column 2) and the found tracks plot.
The Z-fraction is lower in the bhmu0d data set because the tracking was better (see the bottom right plot of COT tracking efficiency compared to the bottom left), while the background stayed the same.
Our chamber and counter noise rates are a factor of 10 larger than they used to be, thanks to increased luminosity. I adjusted the numbers in the simulation to match.
Modified 21-November-2005 at 15:47
http://hep.physics.wisc.edu/~jnb/imu/21Nov2005