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Search For New Physics at the TeVatron

This article discusses the search for new physics phenomena at the Tevatron collider, including supersymmetry, extra dimensions, extended gauge theories, and Higgs bosons. It covers upgrades to the CDF and DØ detectors, performance of the Tevatron in terms of luminosity, and specific searches for trileptons, stop and sbottom particles, and generic squarks and gluinos.

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Search For New Physics at the TeVatron

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  1. Search For New Physics at the TeVatron Jean-François Grivaz LAL-Orsay http://www-cdf.fnal.gov/physics/exotic/exotic.html http://www-d0.fnal.gov/Run2Physics/WWW/results.htm Saclay 11-April-2005

  2. Chicago  CDF DØ Tevatron p source Main Injector & Recycler The Tevatron at Run II • New Main Injector • + Recycler • Higher energy • (1.96 TeV vs 1.8 TeV) • => Higher cross sections • (~30% for the top) • Higher antiprotonintensity • 6x6  36x36 bunches • (3.5 s  396 ns) • antiproton “recycler” • => Higher luminosity Saclay 11-April-2005

  3. The CDF and DØ upgrades • New tracking: silicon and • fibers in 2T magnetic field • Upgraded muon system • New DAQ and new trigger • (commissioning displaced track) • New silicon and drift chamber • Upgraded calorimeter (plug) • and muon system • New DAQ and new trigger, • (displaced track trigger) … and new software (C++, OO) Saclay 11-April-2005

  4. Luminosity performance In 2004: • Peak luminosity: • 4 - 8 1031 cm-2 s-1 • Weekly delivered: • 8 - 16 pb-1 • Data taking efficiency: • 80 - 90% • Physics quality data: • up to 390 pb-1 • analyzed as of Moriond-05 1032 Saclay 11-April-2005

  5. Searches for New Phenomena Supersymmetry: (m)SUGRA, GMSB, AMSB Extra Dimensions: large, warped Extended Gauge Theories: Z’, W’, leptoquarks Higgs bosons: SUSY, SM In back-up slides: RPV, excited leptons, doubly-charged Higgses Not covered : TeV–1 ED, Technicolor, Little Higgs but same signatures as e.g., LED, SM-Higgs, RS-gravitons Real exotics (e.g.monopoles) Saclay 11-April-2005

  6. Supersymmetry Saclay 11-April-2005

  7. (m)SUGRA m0 m1/2 tan() A0 sign() Two main search streams at the Tevatron: • Squarks and gluinos multijets + missing ET • large production cross sections • large experimental backgrounds • Electroweak gauginos with leptonic decays (Trileptons) • low production cross sections • typically low leptonic branching ratios • clean experimental signature Saclay 11-April-2005

  8. Trileptons (I) • Arise from chargino-neutralino • associated production • “Golden” SUSY signature but: • - low cross sections ( BR) • - soft leptons • - taus(esp. at large tan) • Needs large integrated luminosity • Combine various final states (Also decays via W/Z exchange) DØ analysis based on 325 pb1 Combines eel, el, el, l, l and same sign dimuon final states Addresses “just beyond LEP”mSUGRAwith low mass sleptons Saclay 11-April-2005

  9. Trileptons (II) • Two isolated (rather soft) e or  or  • Require some Missing ET •  channel-dependent cuts (e.g. anti Z) • Two same sign muons, or • An isolated third track (no e or  ID) • Main backgrounds: WW, WZ, W, a bit of bb • Altogether: 4 events observed vs 3.9  0.8 expected   3rd (e) Saclay 11-April-2005

  10. Trileptons (III) Now probing “beyond LEP” territory: m()  116 GeV for m(slepton) m() Saclay 11-April-2005

  11. Stop and sbottom • CDF has searched for charged massive particles in 53 pb1 • appear as slow moving (TOF) high pT muons • result interpreted for (meta)stable stop •  m(stop) 108 GeV (isolated) or 95 GeV (non-isolated) • CDF has searched for sbottoms • in gluino decays (156 pb1) • assumes sb1 much lighter than • all other squarks (large tan) • gluino  sb1 b •  4 b-jets + Missing ET • for gluino pairs • the selection requires at least • one b-tag, no isolated lepton • With 2 b-tags: 4 vs 2.6  0.7 expected Saclay 11-April-2005

  12. Generic squarks & gluinos (I) • Strong production of: • sq-sqbar • sq-sq • sq-gl • gl-gl • Main decay modes: • m_sq < m_gl : sq  q • m_gl < m_sq : gl  qq • but also cascades via  or 2 In 310 pb1, DØ has searched along three mSUGRA lines: minimum squark mass m_squark = m_gluino gluinos only (tan = 3, A0 = 0,   0), with scan over m1/2 Saclay 11-April-2005

  13. Generic squarks & gluinos (II) • Example of selection cuts for light squarks: • at least two high pT jets • isolated lepton veto • Missing ET should not be • along or opposite to a jet • Sum of jet pT 250 GeV • Missing ET  175 GeV • 12 events selected vs. 12.8 5.4expected • Main backgrounds left: • (Z  ) + jets • (W ) + jets • QCD negligible QCD m_squark = m_gluino : 3 jets + MET gluinos only: 4 jets + MET Saclay 11-April-2005

  14. Generic squarks & gluinos (III) • Results along the three selected lines: • Minimum squark mass: • m_squark > 318 GeV • Equal squark and gluino • masses: • m_squark = m_gluino • > 333 GeV • (This corner is beyond the indirect LEP exclusion) • Gluinos only: • M_gluino > 233 GeV Saclay 11-April-2005

  15. GMSB with  NLSP (I) Remember the CDF ee + Missing ET event ?…  + gravitino Inclusive search for   Missing ET by both CDF / DØ • Photon = electron without track • Photon ET  13 / 20 GeV • Missing ET > 45 / 40 GeV • Mild topological cuts • Main backgrounds: • EM-jets (or real QCD photons) • + fake Missing ET • electron + photon • + real Missing ET • All determined from the data CDF : 0 vs 0.3  0.1 expected DØ : 2 vs 3.7  0.6 expected Saclay 11-April-2005

  16. GMSB with  NLSP (II) • Interpretation within mGMSB • with: • N = 1 • Mmessenger = 2, •   0, • tan = 15 (aka “Snowmass slope”) • Signal dominated by • chargino-neutralino production Individual limits: m  108 GeV (DØ) (beyond LEP) m  93 GeV (CDF) First CDF-DØ NP combination: m  114 GeV & m  209 GeV Saclay 11-April-2005

  17. Charged Massive Stable Particles In Anomaly Mediated SUSY Breaking (AMSB), the chargino can be almost degenerate with a wino-LSP. It will then appear as a long-lived charged WIMP. DØ has searched for pair production of such charged massive stable particles in 390 pb1. They appear as slowly moving high pT muons, and are identified using the timing information of the scintillator counters of the muon detector. m  174 GeV (beyond LEP) Saclay 11-April-2005

  18. “Superjets” ? CDF @ Run I observed an excess of W + 2/3 jet events with  1 jet “double-tagged” (Secondary vertex + Soft lepton) 13 vs 4.4  0.6 expected An interpretation in terms of light sbottom + RPV () has been suggested (not by CDF) DØ has searched for such an anomaly in 150 pb-1 of Run II data and did not find any. Let’s wait and see what CDF will find… Saclay 11-April-2005

  19. Bs  In SM, tiny BR ~ 3.5 109 (and 25 times smaller for Bd) But in SUSY, a (tan)6 factor could lead to an enhancement by as much as three orders of magnitude Select dimuons originating from displaced vertices, and look inside a mass window: BR limits (95% CL): 3.7 10-7 (DØ 300 pb-1) and 7.5 10-7 (CDF 171 pb-1) Close to getting relevant Saclay 11-April-2005

  20. Extra Dimensions Saclay 11-April-2005

  21. Models of Extra Dimensions • Two classes of models considered: • ADD • 2 to 7 large (sub mm) EDs • gravity propagates • freely in the bulk • KK excitations • cannot be resolved • RS • one 5th (infinite) ED • with warped geometry • gravity is localized • on a brane other than the SM • KK excitations • have spacings of order TeV Saclay 11-April-2005

  22. g g g q GKK GKK g q f f V GKK GKK f f V Large Extra Dimensions Two main search streams at the TeVatron: Real graviton emission Apparent energy-momentum non-conservation in 3D-space  “Monojets” Direct sensitivity to the fundamental Planck scale MD Virtual graviton exchange Modifies SM cross sections Sensitivity to the theory cutoff MS (MS expected to be  MD) Saclay 11-April-2005

  23. Monojets DØ search in 85 pb-1: • Main selection cuts: • one high pT jet ( 150 GeV) • (soft jets from ISR are allowed) • isolated lepton veto • Missing ET away from all jets • Missing ET  150 GeV QCD Main background: (Z ) +jet QCD is negligible 63 events selected 100 +51/-32 expected Large error from Jet Energy Scale (Updated result coming soon) Saclay 11-April-2005

  24. High pT dileptons & diphotons DØ search in 200 pb-1 combines ee and  to maximize the sensitivity Fit of Data to SM+QCD+LED(MS) World tightest limits: MS > 1.36 TeV MS >1.43 TeV w/DØ@Run I in the GRW formalism Also 1.1 TeV: from CDF in dielectrons with 200 pb-1 from DØ in dimuons with 250 pb-1 Saclay 11-April-2005

  25. Randall – Sundrum gravitons Here too, most of the sensitivity is in diphotons (BR = 2ee) DØ uses the same ee + data set as for the LED search 300 GeV RS-graviton DØ Run II Preliminary Two model parameters: Mass and coupling (/MPl) For /MPl = 0.1: M  785 GeV Also 690 GeV from CDF in diphotons with 345 pb-1 Saclay 11-April-2005

  26. Heavy Vector Bosons Saclay 11-April-2005

  27. DØ Run II Preliminary 600 GeV Z’ Z’ in dielectrons Now select only electron pairs (much reduced QCD background) For an SM-like Z’: M  780 GeV Limits for SM-like Z’ and various E6 models Also M > 750 GeV from CDF (200 pb-1) Saclay 11-April-2005

  28. Z’ in dimuons Dimuons vs. dielectrons: lower background but worse resolution Z’ limits in various E6 models For anSM-like Z’: M  735 GeV Also M 680 GeV from DØ (250 pb–1) Combining ee and : M (SM-like Z’)  815 GeV(CDF) Saclay 11-April-2005

  29. Z’ in  CDF in 195 pb-1 4 events (eh,h,hh) vs 2.8  0.5 expected Saclay 11-April-2005

  30. W’ in e CDF in 205 pb-1 mW’ 842 GeV Saclay 11-April-2005

  31. Leptoquarks LQ lq (BR = ) or LQ q (BR = 1 – ) Pair produced  llqq, lqq or qq final states Saclay 11-April-2005

  32. 1st generation Leptoquarks (I) DØanalysis performed in the eeqq and eqq channels (252 pb-1) 2 electrons, 2 jets and Z-veto 1 electron, missing ET and W-veto ST = ET(e1)+MET+ET(j1)+ET(j2) ST = ET(e1)+ET(e2)+ET(j1)+ET(j2) (After all other cuts) 1 event vs0.5  0.1 expected 1 event vs3.6  1.2 expected Saclay 11-April-2005

  33. 1st generation Leptoquarks (II) M  241 GeV( = 1) M  218 GeV( = 0.5) (DØ – Run II) M  256 GeV( = 1) M  234 GeV( = 0.5) (DØ – Run I + Run II) Also CDF with 200 pb-1: M  234 GeV( = 1) M  206 GeV( = 0.5) Saclay 11-April-2005

  34. 2nd generation Leptoquarks 2nd generation LQ in CDF with 200 pb-1 qq : 2 events vs1.9  1.0 expected qq : 3 events vs3.7  0.6 expected M  224 GeV( = 1) M  208 GeV( = 0.5) Saclay 11-April-2005

  35. Leptoquarks in the qq channel Topology = Acoplanar jets + Missing ET Large backgrounds from QCD multijets and from SM processes (Z  jets) Also DØ with 85 pb-1: M  109 GeV 124 events vs 118.5 14.5 expected Saclay 11-April-2005

  36. Higgs bosons Saclay 11-April-2005

  37. SUSY-Higgs @ large tan Hbb coupling enhanced DØsearch for  3b jets (260 pb-1) Saclay 11-April-2005

  38. SM Higgs boson searches LEP indirect: MH < 260 GeV LEP direct: MH > 114 GeV Hint at 115 GeV MH < 130 GeV: Hbb gg H bb hopeless (H  maybe) H(W  l) and H(Z  ll/): best processes Hbb OK for SUSY @ large tan Htt maybe MH >150 GeV: H WW* gg H (W  l)(W* l): best process Also (H WW*)(W l / Z ll) Saclay 11-April-2005

  39. High mass: HWW DØsearch in the ee, e and  + Missing ET final states The WW background is reduced using the spin correlations: smaller ll angle in the Higgs signal For mH = 160 GeV: 20 events observedvs.17.7  1.0 expected Also CDF:   5.6 pb with 200 pb1 Saclay 11-April-2005

  40. Low mass: (Wl)(Hbb) CDF search in 162 pb–1: e/ + Missing ET + 2jets ( 1 b-tag) Similar DØ search (174 pb–1 - e only) with 2 b-tags Still a long way to go… Saclay 11-April-2005

  41. Now LHC Are we going there ? Updated signal and background cross sections Full detector simulation + established analysis techniques + “reasonable extrapolations” + Signal shape (vs. mass window) (but no systematics…) If we are lucky: 3s evidence If not…: 95% CL exclusion of the MSSM range Saclay 11-April-2005

  42. Final remarks The Higgs is not the whole story… With a data sample at least 20 to 40 times larger than at Run I, collected at higher energy with improved detectors, there is a lot of beautiful (but difficult) physics to be done: • W and top masses, top properties, single top production • B physics: Bs mixing, rare Bs decays, Bs and Lb lifetimes • Exploration of new territory (SUSY, LED…): • already well underway • we may be lucky… With a steadily improving collider performance there are still a number of years and fb–1 ahead of us for frontier physics at the Tevatron. Saclay 11-April-2005

  43. Back-up Slides Saclay 11-April-2005

  44. CDF/D0 2 fb-1goal! The Run II Menu With 2 fb-1: • Top mass to  3 GeV • W mass to  30 MeV • Bs mixing to 20 ps-1 • Exclude mH = 115 GeV • And much more… • High pT jets • LED to 2 TeV • SUSY And beyond: Saclay 11-April-2005

  45. RPV with ijkLiLjLk coupling (I) DØ has searched for multilpeton final states arising from SUSY particle pair production with R-parity violating decays of two neutralino LSP’s in the regime where  is small enough so that only the LSP has an RPV decay, and large enough for its lifetime to be negligible. The couplings considered were 121  eeee, eee or ee +  122  , e or ee +  Three isolated (rather soft) e or  Require some Missing ET  channel-dependent cuts (e.g. anti Z) Saclay 11-April-2005

  46. RPV with ijkLiLjLk coupling (II) 121: 0 vs 0.5  0.4 expected (238 pb-1) 122: 2 vs 0.6  1.9 expected (163 pb-1) eee/ A search has also been performed for the 133coupling, in the eeX final state, with   hadrons +  (199 pb-1) Resonant single slepton or sneutrino production via a 211 RPV coupling has also been investigated (154 pb-1) m 200 GeV Saclay 11-April-2005

  47. Excited electrons CDF search in the ee final state (200 pb-1) Z - veto 3 events vs 3.0  0.4 expected (main background = Z) Saclay 11-April-2005

  48. Doubly-charged Higgs Bosons Doubly charged Higgs (from Higgs triplets) are predicted in, e.g., LR-symmetric models CDF has searched for H pair production in 240 pb-1 The signature is a pair of same sign ee, e or  0 ee events vs 1.5 +0.90.6 expected 0 e events vs 0.4 0.2 expected 0  events vs 0.8 +0.50.4 expected Also DØ in  (113 pb-1): M(HL) > 118 GeV M(HR) > 98 GeV Saclay 11-April-2005

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