SUSY

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SUSY Tevatron Results and Physics Potential
Andy White University of Texas at Arlington for
the D0 and CDF Collaborations
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Contents

• SUSY in Run I at the Tevatron
• - examples of analysis not comprehensive
• - parameter space access/coverage
• Tevatron Run II
• - D0/CDF detector upgrades
• - Accelerator, luminosity
• SUSY in Run II at the Tevatron
• - Analyses started
• - Physics potential

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SUSY Cross sections are small !
Indicated ? points are for m1/2 150 GeV m0
100GeV A0 300 GeV tan? 4 ? gt0
Cross sections (pb)
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SUSY in Run I

• - Energy 1.8 TeV
• 100 pb-1 of data analyzed
• Many channels studied
• Classic SUSY - Jets and Met
• Squarks gluinos with leptonic decay(s)
• Gaugino production, leptonic decay
• Stop, Bottom
• Alternatives e.g. GMSB, RPV,

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Some examples from Run I
CDF
D0
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mSUGRA parameter space coverage
D0
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Run II SUSY/Higgs Workshop hep-ph/0003154
Typical Run I results
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Stop and sbottom searches
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Stop and sbottom searches
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D0 results for RPV SUSY tri-leptons
Reinterpretation of trilepton gaugino pair
production results for mSUGRA with R-parity,
Lepton number violation. LSP -gt
Leptons ?ijkLiLjEkC Enhanced multilepton events
Li
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CDF a hint of something new from Run I ??

• - Low probability from SM sources model
  independent study with l, ?, MEt.
• Subject of much speculation! GMSB explanation
  Gravitino LSP?
• Motivation for many searches in Run II

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Run II at the Tevatron

• New accelerator components Main Injector
• Upgraded D0 and CDF detectors
• Higher beam energies larger cross-sections
• Substantially expanded worldwide participation
• SUSY analyses underway for D0 and CDF
• Predictions for Runs IIa, IIb from Fermilab
  Workshop, e.g. SUGRA in hep-ph/0003154.

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CDF upgrades for Run II
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CDF improvements for SUSY searches

• New tracking system (Si and central)
• Extended coverage for electrons and muons
• New forward (plug) calorimeter improves Met
• TOF for charged massive stable particles
• New/improved triggers for MEt, ?

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New forward components of the D0 detector
Intercryostat detector
Forward pre-shower
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D0 improvements for SUSY searches

• Solenoid completely new tracking added
• Improved muon tracking and triggering
• Improved electron id. (preshowers)
• Central track trigger
• Triggering on b jets
• New Intercryostat Detector (jets, MEt)

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Run II SUSY Searches

• Examples of Run II results here are from
  Winter/Spring conferences expect significant
  updates, increased ?Ldt this summer.
• Both experiments use two approaches

Theory/model motivated analysis
Model independent analysis
Optimize analysis with model studies
Generic search safety net
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Jets MEt
The challenge QCD (jets) -gt high rate -gt
residual tail. D0 - study with 4 pb-1 has
shown that, with cuts to reduce fake MEt, the
tail can be understood.
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Jets MEt expectations
Run II 2 fb-1 search region
hep-ph/0003154
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Photons MEt
Gauge mediated SUSY breaking (GMSB) with light
Gravitino LSP can yield ?? MEt
where N is next-to-lightest SUSY particle.
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Observe 2 events, expect bkg 22 events
CDF Run II
From S-W Lee/SUSY 2003
M 2?, N5 1 tan ? 15, ? gt 0
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66 GeV limit from 50 pb-1
D0 Run II
M 2?, N5 1 tan ? 15, ? gt 0
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Tri-lepton final states
?s !
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Tri-lepton final states
42 pb-1
Di-electron sample cuts
Efficiencies few percent Will improve over
LEP-2 with gt300 pb-1
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Tri-lepton final states
Studies for ? channels
D0 Z -gt ?? -gt (e??) (h?)

• Pt(e) gt 12 GeV isolated
• Pt(jet) gt 7 GeV
• - Jet/e not back to back
• - Cut on Z -gt ee
• Use Neural net for tau id.

D0 Run II preliminary 50pb-1
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Tri-lepton final states
CDF Z -gt ? ?
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Tri-lepton final states
Soft cuts to pick up ?-gte, ?. Cuts varied to
optimize S/?B.
Dilepton plus Tau jet
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D0 model independent search in e?

• - Results from 30 pb-1
• - SM mis-ID backgrounds
• Main bkgds Z-gt??, WW, tt
• - Derive ? limits vs MEt cut

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D0 model independent search in e?
100 fb
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Long lived Stop from TOF
CDF GMSB with NLSP stable Stop particle.
?t gt 2.5 ns, Pt gt 40 GeV/c Expect 2.9 0.7 3.1
ev. Observe 7 events M(Stop) gt 108 GeV/c2 at 95
CL (Aleph M(Stop) gt 95)
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Stop, sbottom in Run II
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CONCLUSIONS

• Many interesting results from Run I at O(100
  pb-1)
• Energy and Luminosity upgrades for Tevatron
• Large scale D0 and CDF detector upgrades
• - detectors fully commissioned and taking
  data
• with high efficiencies.
• Comprehensive program of SUSY searches for
• Run II window(s) of opportunity before LHC!

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Fermilab Run II Accelerator Systems
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F. Gianotti talk at D0 Summer 2003 Workshop,
Beaune, France