Slides 5-March-2003

• Using trigger run 5 I look at the projected track position vs the vertex z. The first page is events that satisfied the front trigger, and the second page is those that satisfied the rear trigger. On the left are events from the trigger run, and on the right volunteers from a random set of B-physics events.

  For an event to be in the trigger DST requires that it have both a trigger and a reconstructed BMU-CdfMuon. The front trigger requires that the XFT cough up a 3.1 GeV Pt muon headed for the stub. I don't know the details of the algorithm, but I suspect that the shape of the parallelograms in the trigger data distribution is due to the geometry implicit in the XFT algorithm.

  The rear trigger does not require an XFT track, but to get into the DST we have to have an offline track, so I suspect that the notch cut out of the blob on each side is due to the restrictions on the tracking (which doesn't allow SVX-only). The slope of the notch is about 3.

  Another thing to notice about the rear trigger plots is the rather wide spread of projected z's. There is not a clean cutoff at the front of the BSU as there is in the front trigger. Bob has told me that this doesn't get any better for high Pt muons. This suggests that the eta measured for tracks with larger eta has a good deal more error than advertised.

  The statistics for the volunteers (right-hand plots) are unfortunately rather low. I can't say much about the front trigger hits, except that they are consistent with being where we expect them. The projected Z positions for front triggers (upper) and rear triggers (lower) show that the volunteers are slightly more likely to be in the forward than the rear for a rear trigger.

• I expect that the deviation of the z found by the BMU from the z projected from the track matched to it shouldn't be effected by trigger biases. This turns out to be OK for the rear trigger, but not true in the front (upper is rear, lower is front), so I only look at rear triggered data in what follows. I divided the east and west regions into bands in z (as found by the BMU) and plotted the difference between the BMU z and the z projected from the track. The results show a very clear trend, and when I overlay west and east averages a line fits rather well.

Modified 5-Mar-2003 at 10:41

http://hep.physics.wisc.edu/~jnb/imu/5Mar2003

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