Searches for New Physics at the Tevatron

Transcription

1 Searches for New Physics at the Tevatron Volker Büscher Universität Freiburg Seminar zum Graduiertenkolleg Physik an Hadron-Beschleunigern Freiburg June, 5 Introduction Supersymmetry Squarks and Gluinos Charginos and Neutralinos B s µ + µ, SUSY Higgs bosons Heavy Gauge Bosons Leptoquarks Extra Dimensions

2 The Standard Model and beyond The Standard Model is incomplete: gravitation, dark matter... The Standard Model has many free parameters: Masses Mixing Matrices Gauge couplings Mass (ev) h Z W τ µ e ν t b c s d u Particle Spectrum Mass eigenstates Gauge eigenstates Quarks Neutrinos /α i log Q there must be a more fundamental and complete theory The Minimal Supersymmetric Standard Model (MSSM) is candidate for physics beyond the SM

3 The Standard Model and beyond Strong hint: The hierarchy problem fermion loop corrections to Higgs mass are divergent Higgs mass should be of the order of the cutoff scale (e.g. M Planck ) f H H f in contradiction to indirect evidence for a light SM Higgs boson there must be something beyond the SM that modifies these corrections Two main options:. New physics at O( TeV) loop corrections stay reasonably small. New symmetry that suppresses loop corrections Most straightforward way: cancel fermion loops with boson loops s f H H + H H = f

4 Supersymmetry The idea: particle physics is symmetric under transformation fermion boson implies one supersymmetric partner for each SM particle Superpartners are heavy SUSY must be broken Details of SUSY breaking mechanism unknown need to consider several models: gravity-, gauge-, anomaly-mediated breaking Mass (ev) h Z W τ µ e t b c s d u Particle Spectrum Additional benefits of SUSY: Mass (ev) ± H H,A provides potential dark matter candidate h χ ± χ ± g ~, χ χ 3 4, χ χ ~ l L ~ l R τ τ q ~, q ~ L R ~ t b ~ b ~ ~ t ν L Particle Spectrum predicts gauge unification Grand Unified Theories local supersymmetry quantum gravity /α i 6 /α 5 MSSM 4 /α 3 /α log Q

5 Search for Supersymmetry at LEP Very clean environment, highly efficient searches for large variety of signatures Main limitation: maximum beam energy of 4 GeV Strong limits on SUSY from searches for charginos, sleptons and Higgs bosons: m χ ± > 3.5 GeV, m l 95 GeV, m h > 4.4 GeV Within a given model, can derive mass limits on LSP (dark matter candidate) lim M χ (GeV/c ) LSP Mass Limit in msugra ADLO preliminary µ > m χ (GeV/c ) 54 5 LSP Mass Limit in MSSM with LEP Combined Results Higgs { m TeV/c m top = 78 GeV/c (m top = 75 GeV/c ) 6 A =, M top = 75 GeV/c Charginos (large m ) A =, M top = 8 GeV/c 5 48 Higgs Sleptons } Excluded at 95% C.L. Any A m < TeV/c M top = 75 GeV/c 3 4 tanβ 46 in the corridor Excluded at 95% C.L. 5 tanβ

6 The Tevatron Collider Proton Antiproton Collider _ S W E N Centre-of-mass energy:.96 TeV Integrated Luminosity: fb so far Peak luminosity: _ P8 A P P P3 F GeV p _ A B currently at. 3 cm s with e-cooling: 3 3 cm s Expecting to accumulate 8 fb by 9 E C D Main Injector und Recycler

7 The Tevatron Collider Proton Antiproton Collider _ S W E N Centre-of-mass energy:.96 TeV Integrated Luminosity: fb so far Peak luminosity: _ P8 A P P P3 F GeV p _ A B currently at. 3 cm s with e-cooling: 3 3 cm s Expecting to accumulate 8 fb by 9 E C D Main Injector und Recycler

8 The Tevatron Collider Proton Antiproton Collider _ S W E N Centre-of-mass energy:.96 TeV Integrated Luminosity: fb so far Peak luminosity: _ P8 A P P P3 F GeV p _ A B currently at. 3 cm s with e-cooling: 3 3 cm s Expecting to accumulate 8 fb by 9 E C D Main Injector und Recycler

9 Physics at the Tevatron Tevatron: Proton-Antiproton Collider at s=.96 TeV, collisions every 396 ns Advantage: High centre-of-mass energy production of massive particles (LEP: m < GeV) Disadvantage: Strong Interaction huge event rates for jet production complicated final states: particles from fragmentation of p/ p remnants gluon radiation jets Cross Section Events/pb b Inelastic Scattering mb bb µ b 4 8 nb pb W >lnu Z >ll tt SUSY Trileptons WH 5

10 The Tevatron Experiments µ PDTs µ Scintillation Counters Two General-Purpose Detectors: CDF DØ Electron acceptance η <. η < 3. Muon acceptance η <.5 η <. Silicon Precision tracking η <. η < 3. Hermetic Calorimeter η < 3.6 η < 4. Powerful trigger systems (.5 MHz 5 Hz) Dilepton triggers starting at p T > 4 GeV Jets+ E T triggers with E T > 5 GeV More than.8 fb collected so far Current Average Efficiency 9% µ MDTs Calorimeter Tracking Superconducting Detectors Coil Toroid CFT Shielding CPS FPS Si Barrels F Disks H Disks

11 Search for Supersymmetry Squarks/Gluinos q q q g g g g g q q q q g q q Squarks/Gluinos produced via strong interaction large cross sections at hadron colliders Decays: jets + LSP LSP assumed to be stable (R p conserved) Signature: jets + E T 3 pb collected with dedicated trigger: acoplanar jets + E T Mass region Main Channel Signature Squark Mass (GeV) m~ q > m~ g 4 jets m~ q = m~ g,3 jets m~ q < m~ g jets m q < m g q q j + E T m q > m g g g 4j + E T Gluino Mass (GeV) m q m g q q, q g j/3j + E T

12 Search for Supersymmetry Squarks/Gluinos Searching for one SUSY event with high E T out of 4 p p collisions very sensitive to rare calorimeter problems Missing E T distribution (before quality cuts) PHYSICAL EXAMPLES: MISSING E Deployed extensive data quality monitoring effort offline tools to veto bad blocks of data early online detection and fixing of detector problems

13 Search for Supersymmetry Squarks/Gluinos Fake E T can be caused by: wrong primary vertex energy from additional interactions showers generated by cosmic muons calorimeter noise beam background Wrong PV Hard Scatter Second Interaction Solution: sum transverse momenta of charged particles pointing from primary vertex to jet energy deposition in calorimeter require a minimum charged particle fraction for each jet DØ Run II Preliminary Jet charge particle fraction

14 Search for Supersymmetry Squarks/Gluinos Preselection Stage 3-Jets Analysis before final cut Events / 4 3 DØ Run II Preliminary Data SM bg. Signal Events / DØ Run II Preliminary Data SM bg. Signal Missing ET (GeV) Main backgrounds: Main selection cuts: Missing ET (GeV) Multijets with fake E T W+jets with W eν, µν, τ ν Z+jets with Z ν ν /3/4 jets and large E T separation of E T direction and jets veto events with isolated leptons Mass region Main Channel Signature E T H T = p jet T Exp. Bckgd. Data m q < m g q q j + E T >75 GeV >5 GeV.8±5.4 m q > m g g g 4j + E T >75 GeV >5 GeV 7.±.9 m q m g q q, q g j/3j + E T > GeV >35 GeV 6.±3. 5

15 Search for Supersymmetry Squarks/Gluinos MET ) Squark Mass (GeV/c DØ Run II Preliminary L=3 pb UA UA DØ IA CDF IB DØ IB DØ II χ +/- LEP ~ LEP l no msugra solution q q candidate event ( E T =354 GeV, p j T =64 GeV, pj T =6 GeV) Gluino Mass (GeV/c ) LEP + No evidence for squark/gluino production at the Tevatron m(q ~ )<m( χ New limits in squark/gluino mass plane (msugra: tanβ = 3, A =, µ < ) neglecting contributions from stop production more model-independent interpretation in progress (under discussion in TEVNPWG) Have reached sensitivity beyond Run I and LEP limits )

16 Typical mass spectrum of SUSY particles Mass (ev) ± H H,A χ ± g ~, χ χ 3 4 q ~, q ~ L R ~ t b ~ b ~ ~ t χ ±, χ ~ l L τ ν L h χ ~ l R τ Particle Spectrum

17 Search for Charginos and Neutralinos Production cross section (electroweak) relatively small need clean leptonic signature to suppress backgrounds Golden channel: χ ± χ 3l + E T Experimental Challenge: low-p T leptons need multilepton triggers with low thresholds need efficient lepton identification at low p T Analysis Strategy: two identified leptons plus isolated track (e, µ, τ ) M(slepton) = 6 GeV M(neutralino) = GeV 3rd lepton M(chargino) = 6 GeV next-to-leading lepton leading lepton Events / GeV - - q q - DØ, 3 pb eel selection W χ ± χ W Z Data * Z/γ QCD W + jet / γ WW,WZ,ZZ tt SUSY χ l ± ν l + l χ PT lepton (generator level) (GeV) l3 (GeV) p T

18 Events / 4 GeV Backgrounds: Search for Charginos and Neutralinos Invariant Dimuon Mass 6 * - Z/γ QCD W + jet / γ WW,WZ,ZZ tt DØ, 3 pb µµl selection (GeV) Multijets with fake leptons m µµ Data SUSY Drell-Yan, Z-production with Z ll WW,WZ,ZZ production Events / 4 GeV m T = 3 - p l T E T ( cos Φ l, E T ) 4 - DØ, 3 pb eµl selection Data * Z/γ QCD W + jet / γ WW,WZ,ZZ tt SUSY min (GeV) Main selection cuts: m T Three leptons (ll+track) Missing transverse Energy Selection p l T p l T p l3 T eel > GeV >8 GeV >4 GeV eµl > GeV >8 GeV >7 GeV µµl > GeV >5 GeV >3 GeV ls-µµ > GeV >5 GeV veto events containing Z ll decays

19 Search for Charginos and Neutralinos Results (3 pb ): Selection Expected Background Observed Signal (m χ ±= GeV) eel.±..9±. eµl.3±.3.6±. µµl.75±.57.3±. ls-µµ.66±.37.7±. Combined.93± ±.3 Backgrounds dominated by WZ, WW, Wγ (plus b b for dimuon channels) No evidence for chargino/neutralino production New limits on product of cross section and leptonic branching fraction

20 Search for Charginos and Neutralinos Heavy sleptons: q q W Light sleptons: q q W χ ± χ χ ± χ W Z l l χ χ ν l ± ν l + l l ± l + l χ χ ) BR(3l) (pb) χ σ(χ ± LEP M<: two-body decays into real sleptons M<-6 GeV: good efficiency, high branching fractions ± - Search for χχ 3l+X DØ, 3 pb ± M( χ )=4 GeV, M( χ )=8 GeV tanβ=3, µ>, no slepton mixing heavy-squarks Observed Limit Expected Limit no-mixing M(slepton)-M(χ ) (GeV) -6 GeV< M<: very soft third lepton limit set by ls-µµ-analysis M>: three-body decays via slepton- and W/Z-exchange M : slepton-exchange maximal large BR(3l): 3l-max scenario M : W/Z-exchange dominates small BR(3l): large-m scenario

21 Search for Charginos and Neutralinos ) BR(3l) (pb) χ σ(χ ± ± Search for χ χ 3l+X DØ, 3 pb ± ~ M( χ ) M( χ ) M( χ ); M( l)>m( χ ) tanβ=3, µ>, no slepton mixing 3l-max heavy-squarks Observed Limit Expected Limit -.. LEP large-m Chargino Mass (GeV) New limits constrain SUSY beyond LEP chargino limits 3l-max scenario: m χ ± > 7 GeV heavy-squarks scenario: m χ ± > 3 GeV Assumption: degenerate slepton masses equal branching fractions into e, µ, τ

22 Typical mass spectrum of SUSY particles Mass (ev) ± H H,A χ ± g ~, χ χ 3 4 q ~, q ~ L R ~ t b ~ b ~ ~ t χ ±, χ ~ l L τ ν L h χ ~ l R τ Particle Spectrum

23 Search for Charginos and Neutralinos SUSY mass spectrum likely contains light stau leptons chargino/neutralino decay cascades proceed via stau multiple τ leptons in final state 65% of τ leptons decay hadronically reconstructed as or 3 tracks pointing to narrow energy deposition in calorimeter using neural networks to separate τ -decays from jets HAD EM Track (Type ) () π (3) (QCD Jet) Reference signal: Z τ τ e/µ+hadrons Events / 6 GeV DØ Run II Preliminary L=36 pb Data Z τ τ Background M(µ,τ) (GeV) Events DØ Run II Preliminary L=36 pb Data Z τ τ Background No. of tracks of Tau Candidate

24 Search for Charginos and Neutralinos third lepton (e) Two new DØ trilepton analyses: e/µ + τ + isolated track Selection Expected Background Observed Signal (m χ ±= GeV) eel.±..9±. eµl.3±.3.6±. µµl.75±.57.3±. ls-µµ.66±.37.7±. eτ l.58±.4.4±. µτ l.36±.3.7±. Tau Combined 3.87± ±.3 Muon Tau ) BR(3l) (pb) ± χ Search for χ ± M(χ ) M(χ ) ± χ 3l+X M(χ ); M(slepton) > M(χ tanβ = 3, µ >, no slepton mixing heavy-squarks ) - DØ, 3 pb Preliminary Expected Limit (no τ) Observed Limit Expected Limit σ(χ.3 3l-max third lepton (e).. LEP Chargino Searches large-m Chargino Mass (GeV) Interpretation of results in models with light stau (high tanβ) still in progress

25 Search for Supersymmetry: R-Parity Violation Most general Superpotential contains 45 Yukawa terms leading to violation of Lepton/Baryon-Number: W = W RP C + W RP V W RP V = λ ijk L i L j Ē k + λ ijk L iq j D k + λ ijkūi D j D k couplings are constrained by searches for L- and B-violation, but could be non-zero all terms violate conservation of multiplicative quantum number R-parity need to study SUSY with and without conservation of R-Parity Important consequences of R-parity violation for SUSY collider signatures: LSP can decay into SM fermions: ν l Resonant production of SUSY particles: q µ χ ν l + χ l + l + µ l ν q χ (For non-zero L i L j Ē k -coupling) (For non-zero L i Q j D k -coupling) DØ search channels: χ ± χ χ χ + X 4l + E T + X µ µ + χ µ + j

26 Search for Charginos and Neutralinos: RPV Analyzed up to 4 pb with 5 dedicated trilepton selections: requiring 3 (out of 4) identified leptons very low pt cuts on third lepton (down to 3 GeV) loose E T requirement Backgrounds dominated by DY with fake 3rd lepton, WW/WZ: Selection Background Observed µµµ, eµµ.6±.4 eeµ, eee.5±.4 eeτ.±.4 Interpretation within two reference scenarios: cross section limit [pb] λ σ SUSY (m =5 GeV) 95% CL up.limit (Bayes) D / RunII preliminary (pb) σ λ µ > D Run II Preliminary λ, m = 5 GeV, tanβ = 5 σ GAUGINOS (NLO) σ 95 Present limit D Run I limit experimental limits M χ ± [GeV] ( GeV.c m - )

27 Search for Supersymmetry: RPV Search for resonant smuon production (54 pb ): q µ q χ χ µ µ q µ q # events Reconstructed Neutralino Mass Data: 55 entries. RPV-Signal tt ll * Z/ γ (5-6 GeV) * Z/ γ (6-3 GeV) * Z/ γ (3-5 GeV) * Z/ γ (5-5 GeV) * Z/ γ (>5 GeV) Two muons with p T >8 and p T > GeV Two jets with p T >5 GeV Topological cuts to reduce Z+jets background Reconstruction of Neutralino and Smuon invariant masses Background Expectation: between. and.6 events (depending on mass hypothesis) No excess observed in data: two or less events for all masses Interpretation: limits on λ as a function of Smuon and Neutralino mass λ LQD coupling inv. mass of µ, jet & jet [GeV] Limit for a fixed neutralino mass = 75GeV D Run I Excluded Limit 95%CL, χ =75 GeV D Run I Γ(π e ν)/γ(π µ ν) D RunII preliminary Slepton mass [GeV]

28 Search for Stable Charginos Charginos with small mass difference to LSP can be quasi-stable (Anomaly-mediated SB) slow-moving massive stable charged particle Experimental signature: two high-pt muons with out-of-time scintillator hits Additional Handle: large de/dx in tracker and calorimeter (not used by current analysis) Analysis of 39 pb of data collected with dimuon trigger: require speed of muons to be significantly below c kinematic cuts against Z µµ with poorly measured timing Results (m> GeV): no events observed,.66±.6 events expected new chargino mass limits: 4 GeV (higgsino-like), 74 GeV (gaugino-like) Events/ D Run II Preliminary Data muons GeV staus 3 GeV staus Speed Significance ) (pb) χ + σ (p p χ LEP Excluded D Run II Preliminary - L = 39 pb 95% CL Cross Section Limit NLO Cross Section Prediction Gaugino-like Chargino Mass (GeV)

29 Search for Supersymmetry with Gravitino LSP Gauge Mediated SUSY Breaking: Gravitino G is LSP Assuming Neutralino NLSP: χ γ G Chargino/Neutralino production leads to final states containing γγ+ E T Inclusive search for photons plus E T (63 pb ) Main backgrounds jj, γj and γγ production with fake E T W γ with W eν and fake photon all modelled from data Optimized Cut: E T >4 GeV events observed in data Events / 5 GeV 3 γγ data DØ Background with no genuine missing E T Total background SUSY signal x 3.7±.6 expected from fakes 5 5 Missing E T (GeV)

30 Search for Supersymmetry with Gravitino LSP Mass limits on Chargino and Neutralino (N 5 =, M m =Λ, tanβ=5, µ >): DØ (63 pb ): m χ >8 GeV, m χ ± >95 GeV CDF ( pb ): m χ >93 GeV, m χ ± >68 GeV Tevatron New Phenomena Working Group: first combined Run II result TEVNPWG: m χ >4 GeV, m χ ± >9 GeV ) Neutralino Mass (GeV/c 8 9 (pb) σ BR (γ+x) - CDF pb DØ 63 pb - - expected limit observed limit GMSB γγ+e/ T M=Λ, N=, tanβ=5, µ> PROSPINO NLO QCD Uncertainty Chargino Mass (GeV/c )

31 Search for Supersymmetry: B s µ + µ SM prediction: BR(B s µ + µ )=3.8 9 can be enhanced by non-sm graphs: SUGRA: (tanβ) 6 significant at high tanβ: BR=O( 7 ) complementary to trilepton search Tevatron: large production rate for B s Selection: two isolated muons, displaced vertex Decay length significance Results (limits at 95% C.L.): DØ (3 pb ): 4.3±. expected, 4 observed BR(B s µ + µ )<3.7 7 CDF (364 pb ):.5±. expected, observed BR(B s µ + µ )<. 7 Arbitrary Cut DØ Events/ MeV ω φ J/ψ ψ 6 SM signal ( ) ) Events/5 (MeV/c DØ Run II Preliminary.8.6 Signal region.4 Sideband Sideband Invariant mass (µ µ ) [GeV/c ] Υ(S,S,3S) Mass( µ,µ) [GeV]

32 Search for SUSY Higgs: hb( b) b bb( b) SUSY: hb b-coupling enhanced at large tanβ large cross-sections for hb( b) production Selection: at least 3 b-jets Backgrounds: multijet production (modelled using data, cross-checked with MC) Reconstruction of Higgs boson mass in b b spectrum,%4%!c?= *%K% tanβ DØ Run II Preliminary Excluded at LEP MSSM Higgs bosons bbφ( bb), φ = h, H, A No mixing Max. mixing still no hint Q4#4R for a signal 8 4 m A (GeV) % CL Exclusion, Maximal Mixing Scenario 5 fb - fb - significantly improved limits on tanβ as a function of m A Reminder: SUSY predicts at least one Higgs boson with m 35 GeV tanβ bbφ VH >Vbb combination of b bh and VH analyses should allow a test at 95% C.L. with 5fb (mhmax scenario) 5 5 LEP Excluded M A (GeV)

33 The Standard Model and beyond Strong hint: The hierarchy problem fermion loop corrections to Higgs mass are divergent Higgs mass should be of the order of the cutoff scale (e.g. M Planck ) f H H f in contradiction to indirect evidence for a light SM Higgs boson there must be something beyond the SM that modifies these corrections Two main options:. New physics at O( TeV) loop corrections stay reasonably small. New symmetry that suppresses loop corrections Most straightforward way: cancel fermion loops with boson loops s f H H + H H = f

34 Suche nach neuen Teilchen Schwere Resonanzen Beide Experimente: Suche nach X f f im Run II-Datensatz Zwei-Lepton Selektion, Studium des Massenspektrums jenseits der Z-Resonanz diem Mass Spectrum DØ Run II Preliminary χ / ndf 6.63 / 53 Prob.76 p 4.3 ±.7 p.87 ±.5 σ(z ee) A/σ(Z ee) Z Limits Z Mass, GeV Suche nach Resonanz im Elektron-Elektron-Kanal Daten sind konsistent mit Erwartung aus Drell-Yan- und -Jet-Untergrund Grenzen auf Produktionswirkungsquerschnitt als Funktion der Masse Vielzahl möglicher Interpretationen Beispiel: schwere Eichbosonen Kanal Massengrenze Datensatz Z ee m>78 GeV pb

35 Suche nach neuen Teilchen Schwere Resonanzen Beide Experimente: Suche nach X f f im Run II-Datensatz Zwei-Lepton Selektion, Studium des Massenspektrums jenseits der Z-Resonanz Events / 5 GeV/c 3 CDF RUN II Preliminary ( pb - ) Data All DY Z->µµ QCD+cosmics DY Z->ττ, WW, WZ, t t µµ) (pb) - CDF Run II Preliminary ( pb ) σ Br(X µµ) 95% C.L. limit (spin ) σ Br(Z' µµ) (Sequential) LO.3 σ Br(Z' µµ) (E 6 Z η ) LO.3 - σ Br(Z' Dimuon Mass (GeV/c ) Dimuon mass (GeV/c ) Suche nach Resonanz im Myon-Myon-Kanal Daten sind konsistent mit Erwartung aus Drell-Yan- und -Jet-Untergrund Grenzen auf Produktionswirkungsquerschnitt als Funktion der Masse Vielzahl möglicher Interpretationen Beispiel: schwere Eichbosonen Kanal Massengrenze Datensatz Z ee m>78 GeV pb Z µµ m>735 GeV pb

36 Suche nach neuen Teilchen Schwere Resonanzen Beide Experimente: Suche nach X f f im Run II-Datensatz Zwei-Lepton Selektion, Studium des Massenspektrums jenseits der Z-Resonanz Events / 5 GeV/c High Mass ττ Search CDF Run II Preliminary 95 pb Z ττ Other Backgrounds Control Region Signal Region [GeV/c ] m vis - σ(pp Z )B(Z ττ) [pb] [GeV/c ] m Z - CDF Run II 95 pb Preliminary Z ττ sequential Z cross section 95% CL upper limit Suche nach Resonanz im Tau-Tau-Kanal Daten sind konsistent mit Erwartung aus Drell-Yan- und -Jet-Untergrund Grenzen auf Produktionswirkungsquerschnitt als Funktion der Masse Vielzahl möglicher Interpretationen Beispiel: schwere Eichbosonen Kanal Massengrenze Datensatz Z ee m>78 GeV pb Z µµ m>735 GeV pb Z τ τ m>399 GeV 95 pb

37 Suche nach Leptoquarks Leptoquarks koppeln an Leptonen und Quarks (Motivation: Grand Unification) Beide Experimente: Suche nach LQLQ llq q, lνq q, ννq q im Run II-Datensatz (5 pb ) Selektionen: l+j, l+j+ E T, j+ E T (mit l=e,µ) Hohe LQ-Masse hohe Transversalimpulse für Zerfallsprodukte Number of events/5 GeV Suche nach Überschuß bei hohem S T =p T + p T + p3 T + p4 T - DØ 5pb. Generation Data Total Background LQ (4 GeV/c ) S T (GeV) Verbesserte Massengrenzen:. Generation: m>56 GeV für BR(eq)=. Generation: m>5 GeV für BR(µq)= Alle Generationen: m>7 GeV für BR(νq)= Events Generation Data = 4 GeV 3.5 DØ Run II Preliminary Data = 4 GeV m LQ Z(+jets) µµ(+jets) tt [GeV] S T

38 Models of Extra Dimensions ADD Model Gravity propagates in several large extra dimensions Kaluza-Klein Tower of gravitons with small mass spacing RS Model Gravity propagates in one infinite extra dimension with warped geometry Kaluza-Klein Tower of gravitons with mass spacing of O(TeV)

39 Search for Extra Dimensions Graviton Production Graviton produced recoiling against quark/gluon Large Extra Dimension (ADD): Kaluza-Klein tower of many gravitons g G n q G n sizeable cross-sections Gravitons escape detection monojet signature g g q g Events / 4 DØ Run II Preliminary 3 Data MC Signal Analyzed 85 pb collected by Jets+ E T trigger: Jet p >5 GeV, E T >5 GeV +5 3 events expected (mainly Z ν ν) 63 events observed limit on M D : >68 GeV missing ET Update with more data and improved JES in progress

40 Search for Extra Dimensions Diphoton/Dilepton Production Corrections to diphoton/dilepton cross-sections via graviton-exchange: q l + q l + g l + q γ, Z l q G n l g G n l Analyzed pb of diem-data: diem Mass Spectrum Events/ GeV DØ Run II Preliminary diem Mass, GeV No excess of events at high invariant masses World s best limit on fundamental Planck scale M>.43 TeV (GRW convention)

41 Search for Extra Dimensions Graviton Production Randall-Sundrum Model: First Kaluza-Klein excitation with mass of order TeV Free parameters: coupling parameter k/m P l and mass of first excitation Search for resonant Graviton production in diphotons and dileptons (6 pb ): Events / GeV DØ Run II, 75 pb a) Data Total Background SM Background QCD Background 3 GeV RS Graviton k / M Pl DØ Run II pb RS Model 95% C.L. Excluded Domain µ µ ee+γγ & combined DiEM Mass (GeV) Graviton Mass (GeV) No evidence for heavy resonance Limits on RS-Graviton couplings as a function of mass For k/m P l =.: M G >785 GeV

42 Conclusions and Outlook Tevatron Run II searches are exploring new territory beyond existing limits No evidence for any signal yet New Squark/Gluino mass limits up to 34 GeV Chargino/Neutralino search in trileptons has reached sensitivity beyond LEP Considering large variety of SUSY models: with and without R-parity violation gravity/gauge/anomaly-mediated SUSY breaking current limits on chargino mass up to GeV Powerful complementary tests for SUSY via rare decays and Higgs searches World s best limits on extra gauge bosons, leptoquarks and extra dimensions Future prospects are good second-generation analyses have started: will include new channels continuously improving reconstruction techniques much larger dataset: fb by Fall! ) BR(3l) (pb) χ σ(χ ± - - LEP 3l-max large-m Search for ± -. fb -. fb χ χ 3l+X ± ~ l)>m(χ ) M(χ M( χ ) M( χ ); M( tanβ=3, µ>, no slepton mixing - 4. fb - 8. fb ) Chargino Mass (GeV)