From kenbloom@umich.edu Mon Oct 28 12:23:57 2002 Date: Wed, 23 Oct 2002 10:43:25 -0400 (EDT) From: Ken Bloom To: Manfred Paulini Cc: gold@fnal.gov, Michael Schmitt , Victoria Martin , Marjorie Shapiro , hocker@fnal.gov Subject: Re: new muon 10k samples with 4.9.0 I have gone through my now all-too-familiar exercise of doing my usual acceptance study on this sample. This time, I do see some changes from before, but I can build a circumstantial case that it could be a sort of statistical fluctuation. My acceptance for CMUP-minI track Z's is about two sigma lower than in the last pass. Here's a breakdown of relative efficiency by cut: Cut 4.8.5pre1 4.9.0 One CMUP 0.336 0.337 pT >= 20 0.910 0.913 2nd pT >=20 0.570 0.559 Opp sign 0.993 0.979 66 < M <= 116 0.991 0.961 Total 0.1713+-0.0035 0.1619+-0.0029 It looks like it is all coming in the last two steps. I'm not sure why the opp sign cut cuts away so many events in either case, actually. But that last cut on the invariant mass seems pretty different in effect. I've attached a plot of the invariant mass of dimuons passing all but the invariant mass cut (and originating from HEPG 66 <= M < 116) -- black is new, red is old, normalized to equal area. Are the shapes slightly different? Maybe. (Does it go in the right direction, i.e. the old is wider? Maybe not?) Anyhow, can I come up with an explanation for this? I think so. In the previous pass, (15.0 +- 0.8)% of the second legs were BMU muons. In this pass, it's (16.9 +- 0.7)%, significantly larger. Presumably that means less accurate tracking, and less resolution on the Z peak, and more events getting out of the cut. But like I say, it's circumstantial. If someone would like me to try to do some more work on this, I can. I'll note that the bluebeam/miniskirt/keystone sections are still active in this simulation, i.e. we're not using the "standard" tcl files for this. Will that be changing? Best wishes. Ken ------------------------------------------------------------------------------ Ken Bloom, Karma Adjuster Department of Physics 734-763-2329 / 734-936-1817 (fax) University of Michigan kenbloom@umich.edu http://www.umich.edu/~kenbloom [ Part 2, "" Application/POSTSCRIPT 28KB. ] [ Unable to print this part. ]