SUSY particles searches with R-parity violation at DØ, Tevatron SUSY particles searches with R-parity violation at DØ, Tevatron. (λ121 coupling) Introduction Analysis Results Comparison with other experiments Conclusion and prospects 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Final state with λ121 coupling i) Production: Rp conserved  pair of Charginos-Neutralinos, mainly Z* f W* f Production of a pair of ii) Decay: Rp violated with λ121 coupling  Decay of the neutralinos into leptons. eμ ee Final state: eeee, eeeμ, or eeμμ iii) Detector not fully efficient  we search for ee+X, X = e or μ 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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 … 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Plots to check our understanding of the data After selection of 2 tight electrons. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Remaining events and efficiencies Zee Zττ 0.50 ± 0.35(stat) ± 0.15(sys) 0.07 ± 0.11(stat) ± 0.13(sys) tt WW,WZ,ZZ 0.04 ± 0.03(stat) ± 0.06(sys) 0.10 ± 0.04(stat) ± 0.10(sys) Σbkg DATA (310 pb-1) 0.7 ± 0.4 (stat) ± 0.2 (sys) Selection efficiency on signal : ~ 14 % for μ < 0 ~ 13.5% for μ > 0. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Limits for summer 04 conferences : 238 pb-1 (*) (*) (*) W.Beenakker et al PRL 83 (1999) 3780 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Anne-Marie Magnan --- LPSC Grenoble Present preliminary limits: more luminosity (310 pb-1) and better selection cuts tanβ = 5, A0 = 0 Theoretical x-sect σ95 experimental limit m0 = 100 GeV m0 = 250 GeV m0 = 500 GeV μ < 0 Not yet approuved 249 GeV μ > 0 Not yet approuved 271 GeV 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Limits we can obtain in (m0,m1/2) , and on Mχo1 Susygen (scan) v3.00-43, suspect v2.3 m0 (GeV) m1/2 (GeV) m0 (GeV) m1/2 (GeV) 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Anne-Marie Magnan --- LPSC Grenoble 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: λ133 , μ > 0 Theoretical x-sect σ95 experimental limit m0 = 50 GeV, tanβ=5 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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 λ couplings. H1 : limits on λ’1j1(j=1,2) vs msquarks, and in (m0,m1/2), CMS : preliminary study with λ121 and λ122 couplings. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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). 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

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. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Anne-Marie Magnan --- LPSC Grenoble Backup 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Tevatron and DØ detector s = ~2 TeV Time between collisions = ~400 ns. 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Central detectors view 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble

Anne-Marie Magnan --- LPSC Grenoble Some words on R-parity SUSY particles production: masses and couplings depend 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 + L Rp = +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) 25/11/2004 Euro-GRD Supersymmetry Anne-Marie Magnan --- LPSC Grenoble