fancy BackgroundText
fancy none [10.0in,6.2in]
brown Study of in Run II Data
blue with Turgun Nigmanov and Paul Shepard
blue George Pope
blue University of Pittsburgh
blue CDF Collaboration
blue contact: gpope@fnal.gov
green APS Meeting, 05/01/2004
[C]redIntroduction Production
[C]redAnalysis Strategy Our signature is a and another sharing a common displaced vertex. We require:
[C]redData Selection We use a skim of dimuon-triggered events. The total luminosity for the data is . [scale=0.5]jpsimasswindow.eps brown mass plot showing mass window (green) and sidebands (blue) used for fake background calculation.
[C]redThe Backgrounds As the is not fully reconstructed, understanding the background is of greatest importance. The is rare, but the is plentiful. There is potential for a lot of background.
[C]redFake Third Background
We start with the distribution
and apply the scaling
where is the fraction of tracks
and is the fake rate for .
[scale=0.20]run2mass1final3noBsi.eps
We fit a dE/dx pull distribution to determine and K fractions for the sample.
[scale=0.20]bc04_kpiDedx2.eps
We use to obtain pure and K track
samples.
We determine how often the is reconstructed as a .
The probabilities range from to .
[scale=0.20]bc04_fake_prob3.eps
[C]redFake Third Validation We have validated the methodology for the fake third background with an independent dataset that is pure background.
[C]red Background
[C]redFake Background
[C]redBackground Summary The final fake third contribution is events. We are finalizing some systematics so we can not quote the exact magnitude here. For comparison we show the expected shape of the from MC. [scale=0.35]run2mass2dif3noBsi.eps [scale=0.35]bcsignal.eps brown Left: the shape of the predicted fake third background, magnitude TBD. Right: the shape of the predicted signal from a Bgen MC.
[C]redA Signal? [scale=0.5]run2mass2final3noBsi_noback.eps brown Final candidates. mass after all cuts. The high mass events are explained by and fake backgrounds, within uncertainties.
[C]redConclusions The dominant background in this study is from the decay-in-flight and punch-through of the third track which form the candidate tracks for the third muon. Although we believe that we are making correct estimates for this background there are a number of sources of systematic error (such as trigger bias effects in the analysis of the sample) which are still being considered. For this reason we are not prepared at this meeting to give a precise statement of the overall background in the signal region. Nonetheless, we fully expect that once our errors are finalized that a statistically significant signal in excess of four standard deviations for the inclusive will emerge.
This document was generated using the LaTeX2HTML translator Version 96.1-h (September 30, 1996) Copyright © 1993, 1994, 1995, 1996, Nikos Drakos, Computer Based Learning Unit, University of Leeds.
The command line arguments were:
latex2html aps-slides.tex.
The translation was initiated by George Pope on Thu Apr 29 19:25:35 CDT 2004