Muon Slides 27-February-2002

• Bob Handler has been looking at matching scintillator times with his stub times. The plot for the BSU shows the timing of scintillator hits for the scintillators corresponding to the stub (center) and to each side. Note the wide differences between east and west. It looks as though there is a DC level of tracks on the west side. He looks mainly at the front BSU scintillators, but the rear are only a few nsec later.
• The BMU tracking has been duplicated in the Muon and MuonMods area, and is currently under test. The imu Fortran files are now gone, as are most of the scintillator 'hook' routines and the support for e1.exe and e5.exe. When the BMU stub-finding is verified, the last of the imu and imuMods files will be removed.
• I used a datafile generated by Ken Bloom because it was handy for a quick test, with results herein. The phi distribution looks a smidgeon odd, but is the same in both. Whether this curious phi distribution is merely statistical or algorithmic remains to be seen. I suspect statistical. Note that the distribution is the same between both the new (BMU) and old (IMU) stub finding. The t0 and chisquared distributions show some curiosities as well. Note that the t0 is the result of a 3-parameter fit, and is thus only sensible for 4-hit stubs.

  The West and East BMU t0 distributions peak on different sides of 0, suggesting an algorithmic issue in the fitting. The IMU t0 distributions are both offset, which may reflect a genuine issue with the use of t0 in simulation and reconstruction. The chi-squared distributions are quite similar between the old and new reconstructions.

• I ran a simulation of my own, with negative muons in a restricted phi region and with a specified eta, on the west side. The resulting t0's and reconstructed Z positions are displayed here. Something is clearly wrong with the Z reconstruction. Repeating with postive muons gives the same t0 distribution, and with east muons the reverse. The east muons tend not to have a reconstructed Z.

http://hep.physics.wisc.edu/~jnb/imu/27Feb2002

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