SUSY Tevatron Results and Physics Potential

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


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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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CDF: Z ->


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“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

SUSY Tevatron Results and Physics Potential

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