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SUSY particles searches with R-parity violation at D Ø, Tevatron. (λ 121 coupling)

SUSY particles searches with R-parity violation at D Ø, Tevatron. (λ 121 coupling). Introduction Analysis Results Comparison with other experiments Conclusion and prospects. i) Production: Rp conserved  pair of Charginos-Neutralinos, mainly. W *. f. Z *. f. ee. e μ. e μ. ee.

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SUSY particles searches with R-parity violation at D Ø, Tevatron. (λ 121 coupling)

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  1. SUSY particles searches with R-parity violation at DØ, Tevatron.(λ121 coupling) Introduction Analysis Results Comparison with other experiments Conclusion and prospects Anne-Marie Magnan --- LPSC Grenoble

  2. i) Production:Rp conserved pair of Charginos-Neutralinos, mainly W* f Z* f ee eμ eμ ee Production of a pair of Final state with λ121 coupling ii) Decay:Rp violated with λ121 coupling Decay of the neutralinos into leptons. Final state: eeee, eeeμ, or eeμμ iii) Detector not fully efficient we search for ee+X, X = e or μ Anne-Marie Magnan --- LPSC Grenoble

  3. Data sample and SM background • DØ Run II DATA: from sept 2002 to june 2004 •  310 ± 20 pb-1. • preselection : {2 EM objects pT > 7 GeV.c-1} or {1 EM + 1 μ both pT > 5 GeV.c-1.} • Standard Model (SM) background: all processes with ee or eμ final states, generated with Pythia, Alpgen. • Zee, Zμμ, Zττ between 5 and 1960 GeV, • WWlυlυ, WZ, ZZ, • W  lυ • ttbar  ll, • Υ(1s)(2s)  ee, Υ(1s)(2s)  μμ Anne-Marie Magnan --- LPSC Grenoble

  4. Main selection criteria - at least 3 isolated leptons between them and from jets, in fiducial zones. - “tight” electrons: standard cuts on the shape of the cluster in EM calorimeter, requirement of a track in the inner tracking system. - “tight” muons: identified from inner tracking system to last muon chamber. - Triggers: one OR two EM objects, OR one muon and one EM object. m0 = 250 m1/2 = 195 tanβ = 5 μ < 0 Anne-Marie Magnan --- LPSC Grenoble

  5. A example of trigger effect • Selection of 2 tight electrons, triggered by a jet trigger ( unbiaised sample), how many do also trig an EM or a DIEM trigger ? • EM trigger  100% efficient after 50 GeV, 15% eff at 10 GeV. • DIEM triggers  100% efficient after 30 GeV, 50% eff at 10 GeV  we need both triggers … Anne-Marie Magnan --- LPSC Grenoble

  6. Plots to check our understandingof the data After selection of 2 tight electrons. Anne-Marie Magnan --- LPSC Grenoble

  7. Cuts applied to select ee + X • Cuts to remove background: • Z, WZ, ZZ , •  cut on invariant mass of any ee pair Mee [80,100] GeV.c-2. • Z+jets  ll+jets, and a “b” jet which decays into a muon, •  cut on isolation of the muon • γ conversion in e+e-, •  require hits in inner tracker layers • We expect transverse missing energy in the signal •  cut on MET > 15 GeV. Anne-Marie Magnan --- LPSC Grenoble

  8. Remaining events and efficiencies Selection efficiency on signal : ~ 14 % for μ < 0 ~ 13.5% for μ > 0. Anne-Marie Magnan --- LPSC Grenoble

  9. (*) (*) Limits for summer 04 conferences :238 pb-1 (*) W.Beenakker et al PRL 83 (1999) 3780 Anne-Marie Magnan --- LPSC Grenoble

  10. Theoretical x-sect σ95 experimental limit m0 = 100 GeV m0 = 250 GeV m0 = 500 GeV Not yet approuved Not yet approuved μ < 0 μ > 0 271 GeV 249 GeV Present preliminary limits: more luminosity (310 pb-1) and better selection cuts tanβ = 5, A0 = 0 Anne-Marie Magnan --- LPSC Grenoble

  11. m1/2 (GeV) m1/2 (GeV) m0 (GeV) m0 (GeV) Limits we can obtain in (m0,m1/2) ,and on Mχo1 Susygen (scan) v3.00-43, suspect v2.3 Anne-Marie Magnan --- LPSC Grenoble

  12. λ133 , μ > 0 Theoretical x-sect σ95 experimental limit m0 = 50 GeV, tanβ=5 Other couplings ? • We have to set limits with λ133 coupling to be conservative  studied by Anne-Catherine Le-Bihan (IReS, France) , with eeτ final states. • To see how we are sensitive at λ133 coupling with ee (e or μ) final states: Anne-Marie Magnan --- LPSC Grenoble

  13. Results from other experiments • DØ Run I : limits in (m0, m1/2), for μ < 0 and μ > 0, tanβ = 5, 10, with λ121 and λ122 couplings. • CDF Run I: stop mass limits  λ’ couplings. • LEP: limits on mχo1 > 39 GeV and χ±1 > 103 GeV, for λ133 coupling,  available for all λcouplings. • H1 : limits on λ’1j1(j=1,2) vs msquarks, and in (m0,m1/2), • CMS : preliminary study with λ121 and λ122 couplings. Anne-Marie Magnan --- LPSC Grenoble

  14. CMS results with λ121 coupling Dilepton Invariant mass with m0 = 200, m1/2 = 700. Selection: at least 3 leptons (e, μ) and 2 jets (pTe > 20 GeV, pTμ > 10 GeV, pTjets > 50 GeV.) tanb = 2, μ < 0 Lint = 10 fb-1. 5-sigma reach contour for λ223 = 0.06 (lower curve) and λ121 = 0.05 (upper curve). Anne-Marie Magnan --- LPSC Grenoble

  15. Conclusion and prospects • Anne-Catherine Le-Bihan (IReS) is working on λ133 coupling with eeτ final states, • Daniela Kaefer (Aachen, Germany) is also working on λ122 coupling with μμ+X (=e or μ) final states. • We should have combined results for those 3 couplings for Winter 05 conferences. Anne-Marie Magnan --- LPSC Grenoble

  16. Backup Anne-Marie Magnan --- LPSC Grenoble

  17. Tevatron and DØ detector s = ~2 TeV Time between collisions = ~400 ns. Anne-Marie Magnan --- LPSC Grenoble

  18. Central detectors view Anne-Marie Magnan --- LPSC Grenoble

  19. SUSY particles production: masses and couplingsdepend on 5 parameters (mSugra model) : • m0 , m1/2, sign(μ), tanβ, A0. • In our analysis,m0 = 250 GeV, tanβ = 5, A0 = 0. • R-parity number : • Rp = (-1)3B + 2S +LRp = +1 for standard particles. • Rp = -1 for susy particles. • R-parity violating superpotential: • The couplings between susy and standard particles fall into three classes: • - λijk(leptonic final state), • - λ’ijk(leptonic + hadronic final state) • - λ’’ijk(hadronic final state). i,j,k = e,μ,τ or (u,d), (c,s), (t,b) Some words on R-parity Anne-Marie Magnan --- LPSC Grenoble

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