CDF Logo Search for the Supersymmetric Partner of the Top Quark in Dilepton Events,
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We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions. This search was conducted within the framework of the Rp conserved Minimal Supersymmetric extension of the Standard Model, assuming the decay Stop into lepton, sneutrino and b quark is dominant. We searched a total of 1 fb-1 of data collected by the CDF experiment looking for two leptons (ee, eμ, μμ) of opposite electric charge, jets and missing transverse energy. No significant evidence of the stop signal has been found. New limits at 95% confidence level in the stop versus sneutrino mass plane have been set.


Blessed Plots and Tables:

Results (CDF only):
95% CL Bayesian exclusion limits

EPS or GIF
Cross-section upper limits

EPS or GIF

Definitions of Control Regions used in the analysis
(Y axis - dPhi between leptons) :
0 jets

EPS or GIF
≥1 jet

EPS or GIF

Z peak (ee, μμ with InvM∈(76,106), plots) is removed from the rest.
Heavy flavor contribution (bb,cc) is estimated from data.

MET plots for Control Regions with at least one jet are here.
MET Pre-signal plots are here. Corlim tuning curves are here.

Tables:
Pre-Signal definition/# of events

EPS or GIF
Cuts for different Groups

EPS or GIF

Pre-Signal clean up cut :
any object (both leptons and jet) should be 20° away in φ from MET.

Expected (observed) plots (blue dots are excluded,
red squares are not excluded, green stars used for tuning cuts) :
Groups in stop/snu mass plane

EPS or GIF
Expected (with group lines)

EPS or GIF

Tables:
Number of events after all cuts for different cut groups.
Groups a & d

EPS or GIF
Groups b & c

EPS or GIF

(N-1) Met Plots for four cut groups (ee+eμ+μμ) :
Group a

EPS or GIF
Group b

EPS or GIF
Group c

EPS or GIF
Group d

EPS or GIF

Here are separate (ee, eμ, μμ) plots for cut groups a, b, c and d,
as well as for the pre-signal region.


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