Supersymmetry at the Tevatron

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Supersymmetry at the Tevatron

• R. Demina
• University of Rochester

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20 years of SUSY

• And still, no one is prettier
• We like the way she walks, We like the way she
  talks but
• God damn it, where is she?

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Outline

• Data sets
• Tri-leptons
• Jets and missing energy
• Straight up
• With heavy flavor
• Gauge Mediated SUSY Breaking photons with
  missing energy
• Long-lived particles
• Conclusions

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Run II data taking
Presented analyses are based on pre-shutdown
data lt200pb-1
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SUSY production at Tevatron

• 200 pb-1
• 1013collisions
• 80 chargino/ neutralino ?(3l) events produced
• 800 squark/gluino events produced
• To control backgrounds searches based on
  signatures 3 or more physics objects

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Tri-leptons
ee(l)
em(l)

• Chargino/neutralino production three leptons
  and missing energy signature
• Main challenge - weak production ? low cross
  sections
• LEP limits are very restrictive
• Need extremely well controlled backgrounds

(l ) isolated track e, m, t

• Leptonic branching are enhanced if sleptons are
  lighter than gauginos

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eelepton
175pb-1

• 2 Electrons EM clustertrack match
• PTgt12 (8) GeV
• hlt1.1 (3.0)
• Anti-Z
• 15ltMeelt60 GeV
• Df(ee)lt2.8
• Anti-W?(en)g
• gt1hit in silicon or tighter electron likelihood
• Anti tt
• Veto jets with ETgt80GeV
• Anti-Drell Yan
• Missing ETgt20GeV
• Df(eMET)gt0.4

Potential signal
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eelepton

• Lepton isolated track
• PTgt3GeV

• Etmiss x PT(track)gt250GeV

e(signal)2-3
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Tri-leptons

• Summary after all cuts

Add isolated track with PTgt3 GeV
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Combined tri-leptons

• Run 1 cross section limit much improved
• Soon will reach MSugra prediction (in the best
  scenario with low slepton masses)

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Jets and missing energy
85 pb-1

• Squarks and gluions
• Strong production
• larger cross section,
• but really large instrumental backgrounds (2
  orders of magnitude over SM processes)

Final cuts Missing ETgt175 GeV HTgt275 GeV
2 jets ETgt60 (50) GeV 30ltDf(jet,MET)lt165o

• 4 events left 2.67 expected from SM sources (Z/W
  production)
• 17.1 event expected for M025,M1/2100GeV

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Squarks and gluinos

• M025GeV A00 tanb3 mlt0

M(gluino)gt333GeV Run 1 310 GeV
M(squark)gt292GeV
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B-jets and missing energy

• High tan(b) scenario under study sbottom is
  lighter than other squarks and gluino

• 4b-jetsmissing energy
• gt3jets (ETgt10 GeV)
• Missing ETgt35 GeV
• 1 b-tag
• 5.6-1.4 events SM predicted - 4 observed
• 2 b-tags
• 0.5-0.1 events SM predicted - 1 observed

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ggMet
185 pb-1
Missing ETgt40 GeV

• Gauge mediated SUSY breaking at scale L
• Gravitino LSP
• NLSP (neutralino) ?g LSP
• Dominant SUSY mode c20 c1

Signature 2 photons, missing energy PT(photon)gt2
0 GeV in hlt1.1 1 event survived 2.50.5
expected from SM
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Long Live Particles!
d

• LSP charged particle, or
• NLSP charged particle (e.g. stop) with long
  decay time
• Signature isolated track of a rather slow
  particle
• Use TOF system (CDF)
• BG prediction of 2.9 /- 0.7 (stat) /- 3.1
  (sys), with 7 observed

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Conclusions

• Tevatron detectors produce solid physics results
  based on datasets of up to 185 pb-1
• SUSY limits extended beyond run 1
• In trilepton signature
• Missing energy and jets
• Missing energy and b-jets
• GMSB in diphoton final state
• New system (TOF) used to search for long lived
  particles