Supersymmetry at the Tevatron

Marc Hohlfeld

Rheinische Friedrich–Wilhelms–Universitat¨ Bonn on behalf of the CDF and DØ experiments

– p. 1/3 Outline

Introduction Tevatron collider and detectors Physics at the Tevatron Search for Supersymmetry N Direct searches I Search for supersymmetric Higgs bosons I Search for Charginos and Neutralinos I Search for Squarks and Gluinos I Search for long lived particles N Indirect searches

I Search for Bs → g~ ~+ χ1 ~ Summary and outlook 0 χ~ b 2 ~t

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 2/46 Particle Content

Particles in the Minimal Supersymmetric Model (MSSM)

R–parity = +1 R–parity = –1 R–parity = –1 Particle Symbol Spin Particle Symbol Spin Particle Symbol Spin 1 ˜ ˜ Lepton ` 2 Slepton `L, `R 0 1 Neutrino 2 Sneutrino ˜ 0 1 Quark q 2 Squark q˜L, q˜R 0 1 Gluon g 1 Gluino g˜ 2 1 Photon 1 Photino ˜ 2 ˜ 1 Z Boson Z 1 Zino Z 2 1 9 0 1 W Boson W 1 Wino W˜ > 4 Neutralinos ˜ 2 > i 2 0 ˜ 0 ˜ + 1 => 1 Higgs H , H 0 Higgsino H1, H2 2 2 Charginos ˜i 2 h0, A0 H˜ , H˜ 0 1 > 0 1 2 2 > ;> Assumptions in this talk N Consider mSUGRA model

I Relevant parameters: tan , m0, m1/2, A0, sign() N R–parity is conserved LSP (Neutralino) is stable ⇒

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 3/46 Tevatron Parameters

pp collisions at center of mass energy of √s = 1.96 TeV

Run I Run IIa Run IIb √s (TeV) 1.8 1.96 1.96 Bunches 6 6 36 36 36 36 Bunch spacing 3500 396 396 (ns) Luminosity 1.6 1030 9 1031 3 1032 (cm2s1)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 4/46 Tevatron Performance

Run IIa Run IIb

−1 Run IIa: 1.5 fb delivered −1 1.3 fb recorded −1 Run IIb: 1.6 fb delivered −1 1.4 fb recorded

Tevatron coming close to design luminosity for Run IIb N Improved antiproton stacking rate N Peak luminosity 300 1030 cm2s1 Integrated luminosity of 7–8 fb1 by end of 2009 realistic projection

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 5/46 The Detectors Two multipurpose detectors N Identiﬁcation of electrons, muons, taus, jets, missing transverse energy Fast readout electronics Solenoid N Bunch spacing 396 ns Calorimeter Dedicated trigger systems N Rate reduction from 2.5MHz to 50Hz

Central Preshower Central Fiber Detector (CPD) Tracker (CFT)

Muon System Superconducting Coil CFT CPS Proportional Drift Scintillators Tubes (PDT)

NORTH SOUTH

Silicon Strip Detector FPS Central Outer Tracker Mini Drift Tubes (MDT)

Si−Barrels F−Disks H−Disks P P CDF detector Forward Preshower Detector (FPD) N Large tracking volume Silicon Micro Tracker (SMT) DØ detector N Large acceptance for electrons and muons Calorimeter Toroid Solenoid

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 6/46 The Detectors (cont’d)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 7/46 Physics at the Tevatron

Proton−(Anti−)Proton Wirkungsquerschnitte 10 9 10 9

Physics at the Tevatron is characterized by σtot 7 10 7 10 N High center–of–mass energy of the collider Tevatron LHC

5 I 10 5 10 Production of massive particles possible σ I top–quark, Higgs, SUSY particles, b 3 10 3 10 heavy gauge boson,... jet σjet(E T > √s/20)

1 σ 1 N 10 W 10 Particles are produced in strong interaction σ

(nb) Z

σ jet σjet(E T > 100 GeV) I −1 −1 Huge cross section for jet production 10 10 I Need large reduction to see signals SUSY −3 10 −3 10 32 2 1 σt N 7 interactions/crossing at 3 10 cm s jet σ (E > √s/4) jet T −5 σ (M = 150 GeV) −5 Spectators/ULE 10 Higgs H 10

f i (x 1 ) p1 −7 10 −7 10 p1 x1 0.1 1 10 σ^ (x x ) √s (TeV) p x ij 1 2 2 2 N Final states are complicated p f (x ) Hadronisation 2 j 2 I Fragmentation of spectators

incoming hard parton I Additional jets due to gluon radiation hadrons interaction shower

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 8/46 SUSY at the Tevatron

There are three major areas to search for Supersymmetry at the Tevatron N Search for supersymmetric Higgs bosons I Search for Higgs bosons in ﬁnal states I Higgs bosons searches using b–jets N Direct searches for other SUSY particles I Squarks and Gluinos I Charginos and Neutralinos I Long lived particles N Indirect searches Only a few selected topics will be covered in this talk For a comprehensive overview please refer to CDF http://www-cdf.fnal.gov/physics/physics.html DØ http://www-d0.fnal.gov/Run2Physics/WWW/results.htm

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 9/46 Search for SUSY Higgs Bosons

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 10/46 Search for SUSY Higgs Bosons

5 Higgs bosons are predicted in SUSY models N MSSM Higgs sector speciﬁed by tan , mA Neutral Higgs bosons h/H/A can be produced via gluon fusion or in association with jets N Coupling increases with tan2 Large cross section ⇒ At high tan the main decay modes are N h/H/A bb: 90% h/H/A : 10% → →

τe τh Focus on ﬁnal state τµ τh N Golden channels are he and h τµ τe I Large branching fraction, moderate background τµ τµ τe τe N Other channels are less important I Fully leptonic channels: small branching fraction I Fully hadronic mode: huge multijet background τh τh

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 11/46 Search for SUSY Higgs Bosons (2)

Major backgrounds are Z/ and multijet production → N Require isolated lepton and isolated to reduce QCD contribution N Further reduce QCD by requiring large HT = pT P N Veto on events where E/T is aligned with visible decay products to suppress W+jet events Finally reconstruct visible mass N M = (E + E + E/ )2 (p` + p + E/x )2 (p` + p + E/y )2 (p` + p )2 vis q ` T x x T y y T z z

D∅ Preliminary, 1.0 fb-1

hM=160→ττ Z→ττ 2 QCD Events 10 W→µν Z→µµ W→τν WW→lν lν tt 10 e µ channel

0 50 100 150 200 250 Visible Mass (GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 12/46 Search for SUSY Higgs Bosons (3)

CDF (3 channels) N 2 excess in he and h channels I m 150 GeV, tan 50 A N No excess in e channel DØ (1 channel) m (GeV) vis N No excess in h channel N Expect results in he and e channels later this summer

) 100

b -1

p CDF Run II 1 fb - (

) MSSM Higgs→ττ Search ττ Preliminary

→ 10 φ ( Observed BR

) Expected X 1 φ 1σ band → 2σ band pp

( 95% CL upper limits σ 0.1 100 150 200 250 mφ (GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 13/47 Limits

Although there is excess seen by CDF, no evidence for Higgs production (yet) N Set limits in the tan –mA–plane

µ = -200 GeV, M2 = 200 GeV, mg˜ = 0.8 MSUSY – max MSUSY = 1 TeV, Xt = √6 MSUSY (mh ), Xt = 0 (no-mixing) 100 µ<0 CDF 80 no mixing

observed

β 60 max expected mh tan 40 CDF Run II 1 fb-1 MSSM φ→ττ Search Preliminary 20 max mh no mixing LEP 2 0 80 100 120 140 160 180 200 2 mA (GeV/c )

What to expect in the future N More data, more channels, combination with bh bbb result →

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 14/47 Search for Charginos and Neutralinos

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 15/47 Search for Charginos and Neutralinos

Associated production of Charginos and Neutralinos N Via W boson or Squark exchange + Decay of Chargino l q ~+0 − ~0 lχ 1 Z χ2 N ~0 l ~ 0 W bosons and lightest Neutralino q χ χ 1 + 2 ~ 0 ~+ + W χ 1 l N Slepton and neutrino ~ l + q + 0 ~ l ~ l ~ 0 + χ 1 χ Decay of Neutralino ~ + ~+ 1 q χ l χ ν + q N Z bosons and lightest Neutralino W ν N Slepton and lepton Final state consists of three charged leptons, two Neutralinos and a neutrino 1600

1400 1 pT Trilepton channel is the golden mode for the search of 1200 p2 T Charginos and Neutralinos 3 1000 pT arbitrary units arbitrary 800 N Signature: three charged leptons plus

600 missing transverse energy 400 Challenges 200 N 0 Leptons have low transverse momenta 0 10 20 30 40 50 60 70 80 90 100 p (GeV) N Small cross sections: BR < 0.5 pb T

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 16/47 Backgrounds and Selection

Main background is QCD multijet production N Proton−(Anti−)Proton Wirkungsquerschnitte Very large cross section 10 9 10 9

Require two isolated leptons σtot 7 10 7 10 N Main contributions from Z/ production Tevatron LHC

5 10 5 10 σb

0 ± Data 3 10 3 Search for χ2χ1 → ee+l+X 10 Fake lepton σ (E jet > √s/20) CDF Run II Preliminary jet T 4 Drell-Yan 10 1 σ 1 -1 10 W 10 t t σ

L dt ~ 1 fb (nb) Z

∫ σ jet 3 Dibosons σ (E > 100 GeV) 10 jet T −1 −1 Z + γ 10 10 2 W + γ 10No. of eventsNo. of events SUSY −3 SUSY 10 −3 10 σt σ (E jet > √s/4) 10 jet T −5 −5 10 σHiggs (M H = 150 GeV) 10 1 −7 10 −7 10 0.1 1 10 10-1 √s (TeV) 20 40 60 80 100 120 140 160 180 2 Invariant mass (l1,l2) (GeV/c )

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 17/47 Backgrounds and Selection

Main background is QCD multijet production N Proton−(Anti−)Proton Wirkungsquerschnitte Very large cross section 10 9 10 9

Require two isolated leptons σtot 7 10 7 10 N Main contributions from Z/ production Tevatron LHC

5 Further possibilities to suppress background 10 5 10 σb N Require a third lepton or track 3 N Leptons must have same charge 10 3 10 σ (E jet > √s/20) N Diboson production main contributor jet T 1 1 10 σW 10 D0 RunII Preliminary,1.1fb-1 data σ Z → ττ (nb) Z QCD fakes σ jet 10 σjet(E T > 100 GeV) W W −1 −1 W → lν 10 10 tt → eµ Z → µµ, ee WZ/ZZ SUSY SUSY point (131.232) −3 1 10 −3 10 σt jet σjet(E T > √s/4)

−5 −5 10 σHiggs (M H = 150 GeV) 10 10-1

−7 10 −7 10 0.1 1 10 10-2 √s (TeV) 0 20 40 60 80 100 120 140 Trans. Mass (3rd Track,MET) (GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 18/47 Backgrounds and Selection

Main background is QCD multijet production N Proton−(Anti−)Proton Wirkungsquerschnitte Very large cross section 10 9 10 9

Require two isolated leptons σtot 7 10 7 10 N Main contributions from Z/ production Tevatron LHC

(nb) Z

σ jet σjet(E T > 100 GeV) Three different selection criteria −1 −1 10 10 N Three identiﬁed leptons SUSY −3 −3 10 σ 10 N Two leptons plus additional track t σ (E jet > √s/4) I Higher efﬁciency, but slightly jet T −5 σ (M = 150 GeV) −5 more background 10 Higgs H 10

N Likesign selection −7 10 −7 10 I Sensitive in regions with low pT third 0.1 1 10 lepton √s (TeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 19/46 Selection with Two Leptons

Data Delta phi electrons, Stack_05 -1 Z → mumu QCD DØ Preliminary, 1fb Z → tautau W → mu nu Y(1s) → mumu 104 W gammastar Preselection ZZ 4l tt 2l 2b WW 2l + 2nu 3 WZ 3l + nu 10 Z bb W bb SUSY N 2 Two good reconstructed leptons 10 Anti–Z/ ee, Z/ cuts 10 → → 1

N Small invariant mass 10-1 N Not back–to–back leptons 10-2 10-3

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 ∆ φ (µ, µ)

Lepton 1 Search for χ0χ± → eµ+l+X Data Lepton 1 2 1 Fake lepton 102 χ Drell-Yan ν CDF Run II Preliminary t t -1 Dibosons missing ET Lepton 2 Jet 1 ∫ L dt ~ 1 fb Z + γ W + γ Lepton 2 10

χ No. of eventsNo. of events SUSY Lepton 3

missing ET 1 Signiﬁcant missing transverse energy 0 20 40 60 80 100 120 Missing ET (GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 20/46 E/T N Signiﬁcance of E/T: Sig(E/T) = 2 jet r jets (ET ||E/T) I Only deﬁned for events with jetsP I Rejects events with mismeasured jet energies

Data Z → ee Z → tautau -1 DØ RunII Preliminary 1.1 fb W → e nu 4 10 Y → ee tt 2l 2b 3 WW 2l + 2nu

Events 10 WZ 3l + nu Lepton 1 ZZ 4l or 2l + 2nu 2 10 QCD SUSY 10

Jet 1 -1 Lepton 2 10 10-2

10-3

0 20 40 60 80 100 120 140 160 180 200 missing ET Sig(ET)

E Cuts using /T E/ related cuts T N Cut on E/T itself N Transverse mass cut: m = p E/ (1 cos (e, E/ )) T p T T T I Rejects events with mismeasured lepton energies

Data Z → ee Z → tautau 4 10 DØ RunII Preliminary 1.1 fb-1 W → e nu Y → ee 3 tt 2l 2b 10 WW 2l + 2nu true p WZ 3l + nu T 2 ZZ 4l or 2l + 2nu Events / 1 GeV 10 reco p QCD T true p SUSY T 10 reco p T missing ET 1 missing ET 10-1 large angle reco p reco p T small angle T -2 true pT 10

true pT 10-3

0 10 20 30 40 50 60 70 80 90 100 min(Mtr , Mtr ) [GeV] Signal Background 1 2

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 21/46 N Transverse mass cut: m = p E/ (1 cos (e, E/ )) T p T T T I Rejects events with mismeasured lepton energies

true pT 10-3

0 10 20 30 40 50 60 70 80 90 100 min(Mtr , Mtr ) [GeV] Signal Background 1 2

E Cuts using /T E/ related cuts T N Cut on E/T itself E/T N Signiﬁcance of E/T: Sig(E/T) = 2 jet r jets (ET ||E/T) I Only deﬁned for events with jetsP I Rejects events with mismeasured jet energies

Data Z → ee Z → tautau -1 DØ RunII Preliminary 1.1 fb W → e nu 4 10 Y → ee tt 2l 2b 3 WW 2l + 2nu

Events 10 WZ 3l + nu Lepton 1 ZZ 4l or 2l + 2nu 2 10 QCD SUSY 10

Jet 1 -1 Lepton 2 10 10-2

10-3

0 20 40 60 80 100 120 140 160 180 200 missing ET Sig(ET)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 21/46 Third Track Selection

Select high quality track to account for the third lepton N Track must be isolated in tracker and calorimeter I Efﬁcient for electrons, muons and taus, suppresses tracks in jets N Use hollow cone for isolation I Also efﬁcient for (3 prong) tau decays

Data Z → ee Z → tautau W → e nu DØ RunII Preliminary 1.1 fb-1 2 Y → ee 10 tt 2l 2b WW 2l + 2nu WZ 3l + nu

Events / 1 GeV 10 ZZ 4l or 2l + 2nu ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ QCD © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ £ ¢ £ ¢ £ ¢ £ ¢ SUSY © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ £ ¢ £ ¢ £ ¢ £ ¢ 1 © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ £ ¢ ¥ ¤ £ ¢ £ ¢ £ ¢ © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ ¥ ¤ ¥ ¤ £ ¢ ¥ ¤ £ ¢ ¥ ¤ £ ¢ ¥ ¤ £ ¢

© ¨ © ¨ © ¨ © ¨ -1 ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ £ ¢ ¥ ¤ £ ¢ ¥ ¤ £ ¢ ¥ ¤ £ ¢ ¥ ¤ ¥ ¤ 10 © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ £ ¢ £ ¢ £ ¢ ¥ ¤ £ ¢ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ © ¨ © ¨ © ¨ © ¨ ¡ ¡ ¡ ¡ ¡ § ¦ § ¦ § ¦ § ¦ £ ¢ £ ¢ £ ¢ £ ¢ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ ¥ ¤ 10-2

Electron Muon Tau Tau Jet -3 10 (1 prong) (3 prong) 0 10 20 30 40 50 60 70 80 90 100 Transverse momentum [GeV] Signal Background

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 22/46 Result

No evidence for Charginos and Neutralinos found N Set limits on the production cross section times branching ratio

∼ ∼ ∼ N Translate these limits in mass limits MSSM: tanβ=3, µ>0, M(χ0)∼M(χ±)∼2M(χ0); no slepton mixing 1.6 2 1 1 0.5 CDF Run II Preliminary: 700-1000 pb-1 -1 DØ Run II Preliminary, 0.9-1.7 fb 1.4 σNLO×BR heavy-squarks σ ×BR Uncertainty ∼± ∼0 ∼0 ~ ∼0 NLO 0.4 M(χ )≈M(χ )≈2M(χ ); M(l)>M(χ ) 95% CL Upper Limit: observed 1 2 1 2 1.2 95% CL Upper Limit: expected

BR(3l) (pb) BR(3l) (pb) tanβ=3, µ>0, no slepton mixing BR(3 leptons) (pb) Expected Limit ± 2σ × ××

) 1 1 ) ) ± Expected Limit ± 1σ 00 22 0.3 ∼ χ 0 2 ∼∼ χχ ∼

3l-max Observed Limit χ ±± 11 ( ∼∼ σ χχ Expected Limit 0.8 Excluded (( LEP by LEP σσ 0.2 0.6

0.4 0.1 large-m 0.2 0 0 100 110 120 130 140 150 160 0 100 110 120 130 140 150 160 Chargino Mass (GeV) Chargino Mass (GeV/c2) Cross section limit: BR 0.06 pb Cross section limit: BR 0.2 pb ˜ 3`–max scenario (m˜ & m ) mSUGRA model without `–mixing `R ˜1 N m > 145 GeV N m > 130 GeV ˜1 ˜1

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 23/46 Search for Squarks and Gluinos

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 24/46 Search for Squarks and Gluinos

Squarks and Gluinos can be produced via strong interaction N Production depends on the masses of the Squarks and Gluinos ~ ~ ~ m(q ) >> m(g ) g ~ q m( ) I Either g˜g˜, q˜g˜ or q˜q˜ ~ ~ = gg production dominant ~ m( ) Final state: 4 jets + E q N Decays of Squarks and Gluinos T m( ) I Squarks: q˜ q˜0 → 0 ~ ~ I Gluinos: g˜ qq˜ m(g ) ~ m(q ) → ~ ~ Three different analysis scenarios qg production dominant Final state: 3 jets + ET ⇒ Squark Mass 1 q˜q˜: 2 jets + E/T (Dijet analysis) ~ ~ 2 q˜g˜,q˜q˜: 3 jets + E/T (3–jet analysis) m(g )>> m(q ) ~ qq~ production dominant 3 g˜g˜: 4 jets + E/T (Gluino analysis) Final state: 2 jets + ET

~ Gluino Mass m(g )

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 25/46 AtResultsthe endfromcutsDØonbasedE/ andonH1 fbare1 ofoptimizdataed for every selection T T DØ Preliminary 3 CDF Run II Preliminary 4 10 10 -1 Data Data (Lum = 1.1 fb ) W→ lν + jets QCD Selection Z→Signal νν + jets Efﬁciency (%) Data Background DiBoson tt 3 WW,WZ,ZZ W(e ν)+jets 10 + - Z→ l l + jets +0.96 102 +1.32 single-t W(µ ν)+jets Dijet Signal 7.05 0.39 5 7.47 1.06 W(τ ν)+jets 0.88 Events/40 GeV Events/40 GeV 1.02 Events / 20 E/ Z(e e)+jets 2 T distribution 10 ⇐ +1.11 +1.26 Z(µ µ)+jets Z(τ τ)+jets 3–Jet 6.66 0.37 6 10 6.10 0.37 1.01 1.16 Z(ν ν)+jets tt 10 +0.81 +5.56 Gluino 5.74HT0distr.35ib0.ution72 34 33.35 0.814.92 ⇒ 1 1

0No50 e100vidence150 200 250 f300ound350 400for450 production500 of Squarks and10-1 Gluinos at Tevatron 200 300 400 500 600 700 800 900 ET (GeV) HT [GeV]

Squark and Gluino Selection

Common selection for all three analyses DØ Preliminary Data N W→ lν + jets 2 acoplanar jets and large E/T 300 Z→ νν + jets tt WW,WZ,ZZ - I 1 or 2 additional jets (3–jet, Gluino analysis) Z→ l+l + jets 250 single-t

Events / 5 Signal N Reject events with electrons or muons 200

I Suppress W and Z events 150

100 N Veto on events where E/T is aligned with jets I Reject events with mismeasured jets 50

0 0 20 40 60 80 100 120 140 160 180 ∆φ (E ,any jet) (degrees) min T Jet Jet true jet p Jet 1 T reco jet p T Signal conﬁguration ⇐ QCD background Neutralino ⇒ missing ET Neutralino reco jet p Jet 2 T

Missing ET true jet pT

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 26/47 DØ Preliminary Data W→ lν + jets 300 Z→ νν + jets tt WW,WZ,ZZ - Z→ l+l + jets 250 single-t

Events / 5 Signal 200

150

100

50 1 0 Results from DØ based on 1 fb of data 0 20 40 60 80 100 120 140 160 180 ∆φ (E ,any jet) (degrees) min T Jet Jet Selection Signal Efﬁciency (%) Data Backgtrueround jet p Jet 1 T Dijet 7.05 0.39+0.96 5 7.47 1.06+1.32 reco jet p 0.88 1.02 T 3–Jet Signal6.66conﬁgur0.37+1ation.11 6 6.10 0.37+1.26 ⇐ 1.01 1.16 Gluino 5.74 0.35+0.81 34 33.35 0.81+5.56 QCD background0.72 4.92 Neutralino ⇒ missing ET Neutralino Jet 2 reco jet p No evidence found for production of Squarks and Gluinos at Tevatron T Missing ET true jet pT

Squark and Gluino Selection

Common selection for all three analyses N 2 acoplanar jets and large E/T I 1 or 2 additional jets (3–jet, Gluino analysis) N Reject events with electrons or muons I Suppress W and Z events

N Veto on events where E/T is aligned with jets I Reject events with mismeasured jets At the end cuts on E/ and H are optimized for every selection T T DØ Preliminary 3 CDF Run II Preliminary 4 10 10 -1 Data Data (Lum = 1.1 fb ) W→ lν + jets QCD Z→ νν + jets DiBoson tt 3 WW,WZ,ZZ W(e ν)+jets 10 + - Z→ l l + jets 102 single-t W(µ ν)+jets Signal W(τ ν)+jets Events/40 GeV Events/40 GeV Events / 20 E/ Z(e e)+jets 2 T distribution 10 ⇐ Z(µ µ)+jets Z(τ τ)+jets 10 Z(ν ν)+jets 10 tt HT distribution ⇒ 1 1

0 50 100 150 200 250 300 350 400 450 500 10-1 200 300 400 500 600 700 800 900 ET (GeV) HT [GeV]

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 26/47 Event Displays

Highest E/T events Dijet analysis Gluino analysis E/ = 368 GeV E/ = 321 GeV T T HT = 489 GeV HT = 464 GeV jet1 jet2 jet1 jet2 pT = 282 GeV, pT = 174 GeV pT = 254 GeV, pT = 77 GeV, jet3 jet3 jet4 pT = 33 GeV pT = 67 GeV, pT = 66 GeV

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 27/46 Results

The analyses are optimized for three benchmark scenarios N Vary m0 and m1/2, other parameters constant: A0 = 0, < 0 and tan = 3/5

-1 -1 DØ Preliminary, 0.96 fb CDF Run II Preliminary L=1.1 fb 600 600 observed 95% C.L. observed +/-1σ tanβ=3, A =0, µ<0 ~ 0 obs. ISR/FSR syst. incl. g expected 95% C.L. ~ = M q

CDF II 500 M 500 3-jets inclusive

A0=0, tanβ=5, µ<0 UA2 400 400 ))

no mSUGRA 22 UA1 UA2 DØ IA UA1 CDF IB solution no mSUGRA 300 300 solution Squark Mass (GeV) Squark

DØ IB (GeV/c (GeV/c qq ~~

200 MM 200 FNAL Run I

100 100 LEP

LEP 1 + 2 ~ 0 m(q) < m(χ∼ ) 0 1 0 100 200 300 400 500 600 0 0 100 200 300 400 500 600 Gluino Mass (GeV) 2 M~ (GeV/c ) Mass limits g N Squarks: 391 (375) GeV Gluinos: 309 (289) GeV

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 28/46 Search for long lived particles

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 29/46 Search for CHAMPS

Search for long lived Charged Massive Particles CDF Run II Preliminary (1.0 fb-1) Central µ, p > 40 GeV N Particles do not decay inside the detector 102 T Background Prediction N Highly ionizing and penetrating 220 GeV/c2 Stop 10 Signature in the detector: “slow muon” 1

N Particle penetrates cal and muon system Events / 10 GeV N Use time–of–ﬂight system to measure 10-1 0 50 100 150 200 250 300 Signal expected at high mass 2 Mass from track momentum and β (GeV/c ) TOF N Background sits at low mass

CDF Run II Preliminary Main background components 10 Stop Production cross section (NLO) Cross section limit from central µ N Cosmic muons and instrumental

L dt = 1.03 fb-1 background 1 ∫ Interpreted in SUSY models with one 10-1 compactiﬁed extra dimension Cross section (pb) Cross N In these models Stop is the LSP -2 10 100 120 140 160 180 200 220 240 260 Stop Mass (GeV/c2) Mass limit: m˜ > 250 GeV t

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 30/46 Search for Long lived Gluinos

Long lived Gluinos are predicted in several models N For example split SUSY Gluinos can stop inside the detector N Can decay at random times Not related to any beam crossing ⇒ N Decay can also occur if no beam is in the machine Very hard to model trigger for these events Need a good model for the alive time of the detector

DO, L=410 pb-1

100 hours 18 hours 1 <3 hours Cross Section Limit (pb)

-1 10 150 200 250 300 350 400 450 500 550 600 Gluino Mass (GeV) No evidence for stopped Gluinos

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 31/46 Indirect searches

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 33/47 Search for Bs → + + New physics can also be observed indirectly b W µ The decay Bs is a very good candidate t υ → − l − N Decay is a ﬂavor changing neutral current s W µ + I In the SM it is forbidden at tree level b µ Small branching fraction: H d BR(⇒ B ) = (3.4 0.4) 109 − s → s µ N Enhancement in SUSY models: (tan )6 Blind analysis Predict events in signal region from sidebands ⇒ N Good agreement between number of events predicted and observed N No observation Upper limits on the branching fraction ⇒ ) 2.5 2 DØ Run IIb Preliminary Signal region 2 Sideband 1 Sideband 2 Current limits 1.5 N DØ (2 fb1): BR(B ) < 9.3 108 1 s → 0.5 1 7 Events/5 (MeV/c N CDF (0.78 fb ): BR(Bs ) < 1.0 10 0 4.6 4.8 5 5.2 5.4 5.6 5.8 6 6.2 6.4 → Invariant mass (µ+ µ-) [GeV/c2]

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 33/46 Conclusion

Summary N Tevatron, CDF and DØ are performing well I Already collected more than 2.7 fb1 of data I Nearly factor three more than the data used in the results presented here N SUSY searches probing new regions in phase space I New mass limits beyond LEP2 limits Tevatron will further probe Supersymmetry in so far uncovered territory

O. Buchmueller et al., arXiv:0707.3447v1

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 35/47 – p. 2/2 – p. 3/2 BACKUP SLIDES

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 36/47 Search for Stop Quarks

Due to mixing in third generation, Stop can be light N Can be pair produced at the Tevatron 0 If Stop is light enough it can only decay into c1 0 N The decays t1 and b1 are forbidden Major background contributions are N W+jets, Z+jets and multijet production Selection strategy N Select events with acoplanar dijets N Reject events with isolated electrons, muons or tracks

N Require large E/T and H/T N Apply heavy ﬂavor tagging to reduce light jet contributions from background Optimize selection for different mass points

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 37/47 Search for Stop Quarks (2)

Main background after ﬁnal selection N W( `) = jets and Z( ) + jets N Bac→kground varies betw→een 57 and 82 events depending on Stop mass Signal efﬁciencies N Range from 0.1% to 5% depending on Stop and Neutralinos mass Data is in agreement with the SM expectation

Mass limits N Stop: mt˜ > 160 GeV 0 N Neutralino: m1 > 75 GeV

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 38/47 Search for GMSB

In Gauge Mediated SUSY Breaking (GMSB) models the Gravitino G˜ is the LSP N If the Chargino ˜0 is the NLSP it decays to Gravitinos: ˜0 G˜ 1 1 → N Final state consists of two photons and E/T due to escaping Gravitinos Search for inclusive +E/ events with 1.1 fb1 of data T

3 10 D∅ Preliminary 1.1 fb-1 data γγ Major background components W/Z+γγ 2 10 electron mis-ID N / 3 GeVN / 3 GeV N E/ jet mis-ID Events with true T 10 SM + signal Λ=75 TeV SM + signal Λ=90 TeV I W+jets/, tt

1 N Events with instrumental E/T I Multijets and direct 10-1 production, Z ee → 0 20 40 60 80 100 120 140 160 180 200 Diphoton selection yields 2341 events Missing E (GeV) T

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 39/47 Search for GMSB (2)

Search for the signal in the high E/ region (for different energy scales ) T

E/T Background Data Signal (GeV) true E/T fake E/T Total = 75 TeV = 90 TeV > 30 1.16 0.14 9.62 1.12 10.8 1.1 16 28.3 1.0 8.7 0.3 > 60 0.19 0.07 1.44 0.43 1.6 0.4 3 18.1 0.8 6.4 0.3

D∅ Preliminary 1.1 fb-1 LO cross-section (fb)

σ NLO cross-section expected limit 102 observed limit No evidence for a signal Energy scale and mass limits 10 100 120 140 N > 92 TeV mχ0 [GeV] 1 N m > 231 GeV, m 0 > 126 GeV 180 200 220 240 260 ˜1 ˜1 mχ+ [GeV] 1

70 75 80 85 90 95 100 105 110 Λ (TeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 40/47 Search for GMSB (3)

Search for long lived Neutralinos N In GMSB models pair production of Gauginos is dominant N Gauginos decay into the lightest Neutralino I Final states consists of a delayed photon, jets and E/T Main selection criteria N Select events with time delayed photon N Require large E/T

Mass limit (depending on lifetime) 0 N m˜1 > 101 GeV for = 5 ns

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 41/47 Search for Stops in the Dilepton Channel

Search for scalar top quarks in ﬁnal states with two leptons and two b–quarks N t˜decays dominantly into b`˜ if t˜ b and t˜ b0 are forbidden → 1 → 1 Main selection criteria N Two isolated leptons N At least two jets, highest pT jet must be tagged as b–jet (only channel)

N Signiﬁcant E/T N Other kinematic variables: invariant mass, scalar sum of all pT

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 42/47 Search for Stops in the Dilepton Channel (2)

Background Data Signal tt Diboson Total Point A Point B ee 7.4 20.2 31.7 2.7 34 26.0 1.5 17.3 0.6 e 2.3 0 2.9 0.4 1 3.1 0.2 3.3 0.4 Good agreement of data and SM prediction

Mass limits in m˜–m plane t ˜ N Largest mt˜ limit: mt˜ > 186 GeV (for m˜ = 71 GeV) N Largest m˜ limit: m˜ > 107 GeV (for mt˜ = 145 GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 43/47 Search for Sbottom Quarks

For high tan the ˜b–mass eigenstates have large separation N Sbottom quarks might be light enough to be pair produced at the Tevatron ˜ 0 N Assume 100% branching fraction of b into b1 Final state consists of two b–jets and E/ T Event selection N At least two high pT jets, one jet must be tagged as b–jet N Require signiﬁcant E/T N Veto on isolated leptons

22 6 -1 -1 20 CDF Run II Preliminary, 295 pb CDF Run II Preliminary, 295 pb 18 5 Data Data

16 Events/5 GeVEvents/5 GeV

Events/10 GeVEvents/10 GeV Mis-Tag Mis-Tag 14 4 QCD (HF) QCD (HF) 12 EWK+Top EWK+Top 10 3 Signal Signal ~ 2 ~ 2 (M(b )=160 GeV/c , 8 (M(t )=120 GeV/c , 1 1 2 ∼0 2 ∼0 2 M(χ1)=80 GeV/c ) 6 M(χ1)=50 GeV/c ) 4 1 2

0 0 0 50 100 150 200 250 300 350 400 0 50 100 150 200 250 1st Leading Jet ET (GeV) Missing ET (GeV)

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 44/47 Search for Sbottom Quarks (2)

Data is well described from SM prediction -1 CDF Run II Preliminary (295 pb )

120) observed DØ Run II 2 -1 Observed expected L = 310 pb CDF Run2 : Theoretical uncertainty 100 Expected limit incl. PDF, and renormalization and factorization scale 100 D∅ Run 2 LEP D∅ Run2 : Theoretical uncertainty ) (GeV/c 0 s=208 GeV 1 CDF Run 1 incl. renormalization and ∼ χ factorization scale 0 ) LEP ∼ 1 χ M( ) 0 80 1 χ

)=M(b)+M( ~ 1 CDF Run I 60 b 50 ) = M(b) + M( -1 ~ M( b 88 pb

Neutralino Mass (GeV) Neutralino M( 40

0 0 50 100 150 200 0 0 20 40 60 80 100 120 140 160 180 200 220 Sbottom Mass (GeV) ~ 2 M(b1) (GeV/c ) Mass limits 1 N DØ (310 pb ): m˜b > 222 GeV 1 N CDF (290 pb ): m˜b > 195 GeV

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 45/47 Search for Stop Quarks

Search for scalar top admixture in ttevents in the lepton+jets channel N Stop quarks are pair produced N Decay channels ˜ + 0 I t1 b1 bW 1 I t˜ → b+ → c0 1 → 1 → 1 N (t˜ t˜ ) 0.1 (tt) for masses of 175 GeV 1 1 Start from a selection that is similar to ttselection N Main backgrounds for ttmeasure– ments are W+jet and multijet events N ttevents are of course the major (irreducible) background for stop search I Use Likelihood to discriminate top decays

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 46/47 Search for Stop Quarks (2)

Combine up to ﬁve variables in the Likelihood data data Hitfit reconstructed top 1 mass Hitfit reconstructed top 1 mass -1 Likelihood for stop 175/135 -1 DØ Preliminary 871 pb stop x10 871 pb stop x10 0.2 (175/135) 40 (175/135) 0.18 DO Preliminary ttbar DO Preliminary ttbar Stop 25 Wbb 35 Wbb Wcc Wcc 0.16 Top Wlp Wlp # of entries# of entries # of entries# of entries # of entries W+jets 30 0.14 20 Z+jets Z+jets singletop singletop 0.12 diboson 25 diboson 15 QCD QCD 0.1 20 0.08 10 15 0.06 10 0.04 5 0.02 5 0 0 0 0 50 100 150 200 250 300 0 50 100 150 200 250 300 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 mass[GeV] top mass [GeV] Likelihood

Events observed consistent with SM prediction No evidence for stop quark admixture Upper limits on stop quark production N (t˜1t˜1) < 5.7–12.8 pb (at 95% CL) N Factor 7–12 above the MSSM prediction

SLAC Summer Institute, 08/02/2007 Marc Hohlfeld – p. 47/47