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SUSY Searches at theTevatron Peter Ratoff Lancaster University

SUSY Searches at theTevatron Peter Ratoff Lancaster University. CDF, DØ and Tevatron Status New Run I SUSY Results First Glimpse of Run II Data. The Fermilab Tevatron Collider. Chicago . p. p. 1.96 TeV. Booster. p. CDF. CDF. DØ. Tevatron. p. p sou rce. Main Injector

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SUSY Searches at theTevatron Peter Ratoff Lancaster University

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  1. SUSY Searches at theTevatronPeter RatoffLancaster University CDF, DØ and Tevatron Status New Run I SUSY Results First Glimpse of Run II Data SUSY at the Tevatron IDM2002 Peter Ratoff

  2. The Fermilab Tevatron Collider Chicago  p p 1.96 TeV Booster p CDF CDF DØ Tevatron p p source Main Injector & Recycler DØ SUSY at the Tevatron IDM2002 Peter Ratoff

  3. Run 1b Run 2a Run 2b #bunches 6x6 36x36 140x103 s (TeV) 1.8 1.96 1.96 typ L (cm-2s-1) 1.6x1030 8.6x1031 5.2x1032  Ldt (pb-1/week) 3.2 17.3 105 bunch xing(ns) 3500 396 132 interactions/xing 2.5 2.3 4.8 The Tevatron Run 2 Tevatron upgrade: • Increased energy 1.8 TeV  1.96 TeV • Increased luminosity 0.1 fb-1 2 fb-1  15 fb-1 Detector upgrades: • Higher event rates and backgrounds (electronics, DAQ, trigger) • Considerable expansion of the physics capabilities Physics opportunities: • Top • Higgs • New Phenomena • Electroweak • Beauty • QCD (Run 2a) (Run 2b) (Run 1) SUSY at the Tevatron IDM2002 Peter Ratoff

  4. Detector Commissioning; Timing in; Improve electronics, DAQ and offline First Collisions Run II start DØ roll-in Run 2 in 2001/2002 • Considerable fraction (~25%) of collected luminosity devoted to detector commissioning. • Significant progress in identification of “physics objects”: e, m, jets, electromagnetic and jet energy scales, etc. Currently: • Finishing detector commissioning • Completing triggers and improve DAQ • Debugging, calibration, alignment • Refining reconstruction algorithms • … • Also looking forward to more integrated luminosity!!! 2002 Projected Integrated Luminosity Integrated Luminosity (pb-1) date SUSY at the Tevatron IDM2002 Peter Ratoff

  5. The Upgraded DØ Detector Builds on the strengths of DØ: • Excellent calorimetry with faster readout • Upgraded muon system for better m-ID Augments its tracker and trigger capabilities: • Inner tracking (silicon tracker, fiber tracker) with 2T superconducting solenoid • Preshowers • Pipelined 3-level trigger SUSY at the Tevatron IDM2002 Peter Ratoff

  6. SUSY models • SUSY is the best motivated scenario today for physics beyond the Standard Model • doesn’t contradict precise Electroweak data • predicts light Higgs • unification of gauge couplings at GUT scale • essential element of String Theories • … provides explanation of Cold Dark Matter in the Universe! • SUSY must be broken symmetry (otherwise MSUSY = MSM) • variety of models proposed - differ mainly in the nature of the “messenger interactions” • most experimental results obtained in the context of the SUGRA and GMSB models SUSY at the Tevatron IDM2002 Peter Ratoff

  7. SUSY Phenomenology at Hadron Colliders • Physics environment and expected SUSY phenomenology are quite different at e+e- and Hadron collider machines • production expected to dominate • squarks and gluinos are quite heavy  decay via multi-step cascades  many high PT jets and leptons plus large missing transverse energy SUSY at the Tevatron IDM2002 Peter Ratoff

  8. SUGRA models • SUSY breaking is communicated to the physical sector by gravitational interactions • GUT scale parameters + RGE’s  low-scale phenomenology M0 = common scalar mass M1/2 = common gaugino mass A0 = common trilinear coupling value tanb = ratio of the V.E.V. of the two Higgs doublets sign of m = Higgsino mass parameter Highly constrained minimal SUGRA  LSP is lightest neutralino - a neutral WIMP  excellent CDM candidate SUSY at the Tevatron IDM2002 Peter Ratoff

  9. Single Electron Channel Bckg: W+jets, qcd multijet, tt Cuts: Ete >20 GeV,Etj >14 GeV ( 4), no isolated muons, MET > 25 GeV L = 92.7 pb-1 Sensitive to moderate m0 Complements dilepton and Jets+MET channels Observed events = 72 Expected background = 80 ± 10 DØ SUSY at the Tevatron IDM2002 Peter Ratoff

  10. Single Electron Channel A0 = 0,  < 0 , tan = 3 DØ SUSY at the Tevatron IDM2002 Peter Ratoff

  11. Stop Search Mixing between SUSY partners of tL and tR is proportional to mtop  large mixing lighter SUSY state experimentally accessible Assume sneutrino is LSP... Final state: 2 leptons+jets+MET Drell-Yan, heavy quark pair prod., QCD fakes, diboson production SUSY at the Tevatron IDM2002 Peter Ratoff

  12. Stop Search (II) SUSY at the Tevatron IDM2002 Peter Ratoff

  13. R-parity and its violation • Discrete quantum number R = (-1)3B+2S+L ; is 1 for SM particle,-1 for sparticles • R-parity violation can be introduced by WDL=1 = (1/2)lijkLiLjēk+l'ijkLiQjđk+m' iLiHu WDB=1 = (1/2)l'' ijkūiđjđk Decay of the LSP Signatures maybe very different Single sparticle production possible Whither dark matter candidate mSUGRA with RPV One RPV coupling dominates If coupling large enough, resonant prod. Otherwise pair production SUSY at the Tevatron IDM2002 Peter Ratoff

  14. Decays of Stop Pair Bilinear RPV (“BRPV”) stop   + b Assuming RPV only in 3rd gen. tt+X = tl + b + th + b + X Final state: lepton + hadronic t + 2 jets Bckg: W/Z + jets, multijet, diboson Cuts: pTlepton >10 GeV,th cluster>15, MT(lepton,Met)<35GeV/c2,HT>70,  2jets (ET >15 GeV) L = 106 pb-1 SUSY at the Tevatron IDM2002 Peter Ratoff

  15. Decays of Stop Pair SUSY at the Tevatron IDM2002 Peter Ratoff

  16. Pair Production: di-muon channel LSP Final state: 2m + 4jets No missing ET • Bckg: Drell-Yan, tt, Zmm+jets, Zttmm • Cuts: ptm >15(10) GeV,ptjets >15 GeV, • St > 150 GeV,Mmm >5 GeV,Acoplanarity>0.03 • Run1 L = 77.5 ± 4 pb-1 Events observed = 0 Expected bckg. = 0.18 ± 0.03 ±0.02 DØ SUSY at the Tevatron IDM2002 Peter Ratoff

  17. Pair Production: di-muon channel Run IIa projection 2 fb-1 DØ  < 0 , A0 = 0 , tan = 2 SUSY at the Tevatron IDM2002 Peter Ratoff

  18. Resonant Production:di-muon channel ~ ~ ~  1- 1o _ d Large RPV coupling _ ~ 1o ~ u u d Resonant prod. and decay of LSP via RPV Final state: 2m + 2jets L _ _ d  u d l - d W - l Bckg: tt, Z+2jets, WW+jets Cuts: pTm >20 GeV, pTjets >20 GeV, ST >50 GeV, DR(m-jet) > 0.5 L = 94 ± 5 pb-1 + Observed events = 5 Expected bckg = 5.34 ± 0.07 D SUSY at the Tevatron IDM2002 Peter Ratoff

  19. Resonant Production:di-muon channel Run IIa projection SUSY at the Tevatron IDM2002 Peter Ratoff

  20. SMT CFT CAL Tracks as we know Kinks Large dE/dx Hot cell Photons as we know Impact parameter GMSB models • ‘Messenger’ sector couples to source of SUSY-breaking and physical sector of MSSM (through gauge interactions) • The identity of the NLSP and its lifetime determine the phenomenology c neutralino G slepton llG NLSP SUSY at the Tevatron IDM2002 Peter Ratoff

  21. Light Gravitino Search qq  GGg qg  GGq gg  GGg Final state: MET+jet Bckg: mismeasured multi-jets W/Z + jets, tt, diboson Cuts: MET >50 GeV, removal of events w/ isolated tracks, Df(MET,jet) >90o, Etlead-jet >80 GeV, 0.1 < EMFlead-jet < 0.95 L = 87 pb-1 CDF SUSY at the Tevatron IDM2002 Peter Ratoff

  22. Light Gravitino Search (II) For MET >175 GeV: Events observed = 19 Expected bckg = 21.6 s(PTĞĞ >100GeV) < 3.1pb F > 217 GeV mĞ > 1.1 x 10-5 eV/c2 CDF SUSY at the Tevatron IDM2002 Peter Ratoff

  23. Di-photon Channel Publ. 1998 Neutralino pair production Final state: 2 photons + MET Bckg: multijet, direct photons,Wg, W+jets, Zee Cuts: ETg1 >20 GeV,ETg2 >12 GeV, recon. Vertex, MET>25 GeV L = 106.3 ± 5.6 pb-1 D Events observed = 2 Expected bckg = 2.3 ± 0.9 SUSY at the Tevatron IDM2002 Peter Ratoff

  24. Di-photon Channel (II) D SUSY at the Tevatron IDM2002 Peter Ratoff

  25. Di-photon Channel (III) Run II D Run II preliminary ~ 10 pb-1 MET SUSY at the Tevatron IDM2002 Peter Ratoff

  26. Summary • Comprehensive searches for SUSY have been carried out at the Tevatron exploiting the Run I data to the fullest. • A new era is beginning ... • First preliminary Run II Results … SUSY at the Tevatron IDM2002 Peter Ratoff

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