SUSY
Tevatron Results
and
Physics Potential
Andy White – University of Texas at Arlington
for the D0 and CDF Collaborations
Andy White Physics at LHC
Prague, July 2003
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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 !
Cross sections (pb)
Indicated 
points are for
m1/2= 150 GeV
m0 = 100GeV
A0= 300 GeV
tan = 4
 >0
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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
~
b1  b 
~
0
1
t
1
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 c  10
8
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 -> Leptons
Li
ijkLiLjEkC
Enhanced multilepton
events
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CDF – a hint of something new from Run I ??
- Low probability from
SM sources – model
independent study with
l, , MEt.

0
 G
- Subject of much
speculation! GMSB
explanation:
Gravitino
0
LSP?     G
- 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 preshower
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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)
-> high rate -> 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:
_
~ ~
p p     NN  X    GG  X
where N is next-to-lightest SUSY
particle.
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Observe 2 events,
expect bkg 2±2 events
CDF Run II
From S-W Lee/SUSY 2003
M = 2, N5 = 1
tan  = 15,  > 0
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66 GeV limit
from ~50 pb-1
D0 Run II
M = 2, N5 = 1
tan  = 15,  > 0
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Tri-lepton final states
’s !
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Tri-lepton final states
Di-electron sample + cuts
42 pb-1
Efficiencies ~ few percent
Will improve over LEP-2 with
>300 pb-1
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Tri-lepton final states
Studies for  channels D0: Z ->  -> (e) + (h)
- Pt(e) > 12 GeV isolated
- Pt(jet) > 7 GeV
D0 Run II preliminary 50pb-1
- Jet/e not back to back
- Cut on Z -> ee
Use Neural net for tau id.
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Tri-lepton final states
CDF: Z ->  
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Tri-lepton final states
“Soft cuts” to pick up
->e, . 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->, 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 > 2.5 ns, Pt > 40 GeV/c
Expect 2.9 ± 0.7 ± 3.1 ev.
Observe 7 events
M(Stop) > 108 GeV/c2 at
95% CL
(Aleph M(Stop) > 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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5 discovery curves
~ one year at 1034:
up to 2.8 TeV
~ one year at 1033 :
up to 2.3 TeV
F. Gianotti: talk
at D0 Summer
2003 Workshop,
Beaune, France
~ one month at 1033 :
up to 2 TeV
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