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Search
for Supersymmetric
Top Quarks Decaying to a b Quark and a tau Lepton |
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We search for pair
production of supersymmetryic top quark decaying via R-parity violating
coupling to b-quark and a tau lepton. Presented results are also fully
applicable to the case of the 3rd generation scalar
leptoquark pair
production for
.
This analysis uses 322 pb-1 of data collected by
lepton+track triggers and investigates channels with one of the taus
decaying into leptonically and another one hadronically. In the primary
signal region, we expect 2.26+0.46-0.22 events and we
observe two events. With no excess, we set the
upper limit on
the production cross-section. The lower limit on the stop mass,
assuming
Br(stop-->tau b) = 100%, is 155 GeV/c2 for our nominal
choice of
the NLO cross-section for stop pair production. If theoretical uncertainties due to PDF's and factorisation
scale are taken into acount, the limit is 151 GeV/c2.
- Contacts: Max Chertok, Teruki Kamon, Vadim Khotilovich, Dick Lander and Alexei Safonov
- Data: Run II, 322 pb-1
- Documentation:
PDF
Plots and Tables:
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Production
and Acceptance: |
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Leading LO Feynman diagrams for stop pair production. Same diagrams are applicable to the case of leptoquarks pair production. Plot is available in EPS or GIF format. |
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Full event selection
efficiency of this analysis for region A (events passing all cuts and
also |
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Control and Signal Regions: |
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plots in this section are for electron and
muon channels combined, and loose
cut YT>80
GeV/c was applied to increase statistics for the control regions. |
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Number of jets distribution for events passing all selection cuts and also MT<35 GeV/c2 cut. Plot is available in EPS or GIF format. |
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Number of jets distribution for events passing all selection cuts and also MT<35 GeV/c2 cut. Cut onYT>110 GeV/c was applied. Plot is available in EPS or GIF format. |
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Distribution of the missing transverse energy in events passing all selection cuts and also njet=0 and MT<35 GeV/c2 cuts (region C). Plot is available in EPS or GIF format. |
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Tau candidate number of track distribution for events passing all selection cuts and also njet=0 and MT<35 GeV/c2 cuts (region C). Plot is available in EPS or GIF format. |
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MT distribution for events passing all selection cuts and also njet=0. Plot is available in EPS or GIF format. |
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YT distribution for events passing all selection cuts and also njet=0 and MT<35 GeV/c2 cuts (region C). Plot is available in EPS or GIF format. |
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Distribution of the transverse momentum of the leptonic tau candidate in events passing all selection cuts and also njet=0 and MT<35 GeV/c2 cuts. Plot is available in EPS or GIF format. |
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Distribution of the transverse momentum of the hadronic tau candidate in events passing all selection cuts and also njet=0 and MT<35 GeV/c2 cuts. Plot is available in EPS or GIF format. |
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Exclusion limit in the plane of the cross section of stop pair production vs. stop mass: Observed limit is shown as a red line; expected limit is shown as a band and corresponds to 68% probability; theoretical cross-section (solid blue line) and its uncertainty (dashed blue lines); earlier limit from CDF and LEP search for 3rd generation leptoquarks. Plot is available in EPS or GIF format. |
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Exclusion limit in the plane of the cross section of 3rd generation leptoquark (LQ3) pair production vs. LQ3 mass: Observed limit is shown as a red line; expected limit is shown as a band and corresponds to 68% probability; theoretical cross-section (solid blue line) and its uncertainty (dashed blue lines); earlier limit from CDF and LEP search for 3rd generation leptoquarks. Plot is available in EPS or GIF format. |
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Kinematical Distributions for Final Events: |
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The
plots in this section are for electron and
muon channels combined, and for events passing all
selection cuts and also  cuts
(primary signal region). |
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Distribution of the transverse energy, ET, of the first leading jet. Plot is available in EPS or GIF format. |
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Distribution of the transverse energy, ET, of the second leading jet. Plot is available in EPS or GIF format. |
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Distribution of the transverse momentum of the leptonic tau candidate. Plot is available in EPS or GIF format. |
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Distribution of the transverse momentum of the hadronic tau candidate. Plot is available in EPS or GIF format. |
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Distribution of the missing transverse energy. Plot is available in EPS or GIF format. |
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Distribution of MT(l,MET), the transverse mass of the leptonic tau visible momentum and transverse missing energy. Plot is available in EPS or GIF format. |
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Distribution of YT, the scalar sum of transverse missing energy and visible transverse momenta of the two tau candidates. Plot is available in EPS or GIF format. |
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| Event Displays for Final Events: | |
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Event display for the event
passed all selection cuts and also |
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Event display for the event
passed all selection cuts and also |
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Calorimeter lego plot is available in EPS or GIF format. |
cuts) for stop pair production followed by stop
pair's decay to one leptonic and one hadronic tau and two b-jets. Plot
is available in 
Page http://www-cdf.fnal.gov/internal/physics/exotic/physics/r2a/00000000.template/index.html
was last updated October 6th, 2004 by Stephan Lammel.
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