Andy White Physics at LHC Prague, July 2003
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SUSYTevatron Results
andPhysics 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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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
Contents
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SUSY Cross sections are small !Cr
oss s
ectio
ns
(pb)
Indicated points are for m1/2= 150 GeVm0 = 100GeVA0= 300 GeVtan = 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 ICDFD0
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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 0
1
~
1 bb 01
~
1ct
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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 -> LeptonsijkLiLjEk
C
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
G 0
G 0
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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
analysisOptimize analysis
with model studies
Generic search – “safety net”
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Jets + MEtThe challenge: QCD (jets)-> high rate -> residual tail.
D0 - study with 4 pb-1 has shownthat, with cuts to reduce fake MEt, the tail can beunderstood.
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Jets + MEt expectations
Run II 2 fb-1
search region
hep-ph/0003154
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Photons + MEt
XGGXNNpp ~~_
Gauge mediated SUSY breaking (GMSB) with light Gravitino LSP can yield + MEt:
where N is next-to-lightest SUSY particle.
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From S-W Lee/SUSY 2003
Observe 2 events, expect bkg 2±2 events
CDF Run II
M = 2, N5 = 1 tan = 15, > 0
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D0 Run II
66 GeV limit from ~50 pb-
1
M = 2, N5 = 1 tan = 15, > 0
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Tri-lepton final states
’s !
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Tri-lepton final states42 pb-1
Di-electron sample + cuts
Efficiencies ~ few percentWill improve over LEP-2 with >300 pb-1
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Tri-lepton final statesStudies for channels
- Pt(e) > 12 GeV isolated- Pt(jet) > 7 GeV - Jet/e not back to back - Cut on Z -> eeUse Neural net for tau id.
D0 Run II preliminary 50pb-1
D0: Z -> -> (e) + (h)
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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/cExpect 2.9 ± 0.7 ± 3.1 ev.Observe 7 eventsM(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
~ one month at 1033 : up to 2 TeV
F. Gianotti: talk at D0 Summer 2003 Workshop, Beaune, France
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