CDF Logo Search for Direct Pair Production of Scalar Top and Scalar Bottom Quarks in p-pbar Collisions at sqrt(s)=1.96 TeV
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We report on the search for direct pair production of scalar top quarks and scalar bottom quarks using 295 pb-1 of proton-antiproton collision data recorded by the CDF experiment during Run 2 of the Tevatron. The scalar top (bottom) quarks are sought via their decay into a charm (bottom) quark and a neutralino, which is the lightest supersymmetric particle. The event signature is missing transverse energy and two high-Et jets. In the signal regions the number of observed events are consistent with the number of events expected from Standard Model processes. Thus no evidence for scalar top quark nor scalar bottom quark is observed. 95% CL. limits are set on the cross section times squared branching ratio as function of the mass of scalar top quark and scalar bottom quark, for several neutralino masses, and we extended the exclusion region in the scalar top (bottom) quark mass versus neutralino mass plane. We assume 100% branching ratio for scalar top quark decays into charm quark and neutralino, and 100% branching ratio for scalar bottom quark decays into bottom quark and neutralino.


Blessed Plots and Tables:


Signal Region

Stop (high mass range search)

Missing transverse energy. Open histogram is contribution from stop quark pair production signal (M(stop)=120 GeV, M(neutralino)=50 GeV). EPS or GIF
Minimum azimuthal separation between the direction of the jets and MET. EPS or GIF
Transverse energy of first leading jet. EPS or GIF
Transverse energy of second leading jet. EPS or GIF

Sbottom (medium mass range search)

Missing transverse energy. Open histogram is contribution from sbottom quark pair production signal (M(sbottom)=160 GeV, M(neutralino)=80 GeV). EPS or GIF
Minimum azimuthal separation between the direction of the jets and MET. EPS or GIF
Transverse energy of first leading jet. EPS or GIF
Transverse energy of second leading jet. EPS or GIF

Upper Limit on Production Cross Section (95% CL)


Stop quark search

Cross section times squared of branching ratio vs stop quark mass (for M(neutralino)=50 GeV) EPS or GIF
Cross section times squared of branching ratio vs stop quark mass (for M(neutralino)=55 GeV) EPS or GIF
Cross section times squared of branching ratio vs stop quark mass (for M(neutralino)=60 GeV) EPS or GIF

Sbottom quark search

Cross section times squared of branching ratio vs sbottom quark mass (for M(neutralino)=60 GeV) EPS or GIF
Cross section times squared of branching ratio vs sbottom quark mass (for M(neutralino)=70 GeV) EPS or GIF
Cross section times squared of branching ratio vs sbottom quark mass (for M(neutralino)=80 GeV) EPS or GIF

Exclusion region (@ 95% CL) in M(neutralino) vs M(stop,sbottom)


Stop

Mass limit extraction DOES NOT INCLUDE theoretical uncertainties of the production cross section from uncertainty in PDF, and uncertainty in renormalization and factorization scale. EPS or GIF
Mass limit extraction INCLUDES theoretical uncertainties of the production cross section from uncertainty in PDF, and uncertainty in renormalization and factorization scale. EPS or GIF

Sbottom

Mass limit extraction DOES NOT INCLUDE theoretical uncertainties of the production cross section from uncertainty in PDF, and uncertainty in renormalization and factorization scale. EPS or GIF
Mass limit extraction INCLUDES theoretical uncertainties of the production cross section from uncertainty in PDF, and uncertainty in renormalization and factorization scale. EPS or GIF

Projection of Stop Search to Higher Integrated Luminosity
(Based on earlier search using L=163 pb-1)


Projected 95% C.L. exclusion limit, assuming using the same selection cuts. EPS or GIF

Page 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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