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Overview

Overview. Search for Resonant Slepton Production with the D Ø-Experiment Christian Autermann, III. Phys. Inst. A. R-parity violating Supersymmetry Resonant Slepton Production and Neutralino Decay Data selection and efficiencies Control plots Preliminary Results. Supported by.

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Overview

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  1. Overview Search for Resonant Slepton Production with the DØ-Experiment Christian Autermann, III. Phys. Inst. A • R-parity violating Supersymmetry • Resonant Slepton Production and Neutralino Decay • Data selection and efficiencies • Control plots • Preliminary Results Supported by Bad Honnef, 6.-10. September 2004

  2. DØ Performance Effective Luminosity used for analysis: ∫Ldt= 154±10 pb-1 0.5 fb-1 End of 2003 shutdown Bad Honnef, 6.-10. September 2004

  3. R-parity Violating Supersymmetry S is the particle spin, B is the baryon number, L is the lepton number R-parity violating extension of the MSSM i,j,k = 1,2,3 generation indices Trilepton channel  multi lepton final state Resonant production  two muon and two jets final state Chiral superfields: L: lepton doublet superfield E: lepton singlet superfield Q: quark doublet superfield D: down-like quark singlet superfield λ, λ`, λ``: Yukawa couplings Resonant production at hadronic accelerators References: H. Dreiner, et.al., Search for R-Parity Violation at Run-II of the Tevatron ,hep-ph/9906224 N.Ghodbane, S.Katsanevas, P.Morawitz, E.Perez, SUSYGEN 3, hep-ph/9909499 Bad Honnef, 6.-10. September 2004

  4. Neutralino Production & Decay resonant production decay  R-parity violating production and decay Final state: two (isolated) muons two jets • Other modes: • sneutrino resonance  2 jets, MET & perh. 1 μ • Suppressed Modes: (not considered) • neutralino pair production and decay over λ`211 • t-channel slepton exchange Bad Honnef, 6.-10. September 2004

  5. Run I Exclusion Contour DØ Run I ‘ ‘ ‘ Plots for this point, Limits for M = 75, 100 GeV & Mμ = 200, 300 GeV mSUGRA parameters m0 scalar mass m1/2 gauginos mass parameter A0 trilinear coupling term sign(μ) higgs mass mixing param. tan(β) ratio of the vacuum expect. of the neutral higgs fields m0, m1/2 and A0 are defined at the GUT scale ~ ~ DØ Collaboration, Phys.Rev.Letter 89 (2002), hep-ex/0111053 Bad Honnef, 6.-10. September 2004

  6. Data Sample & Preselection • Total delivered ∫L dt = 209pb-1, good & reconstructed ∫L dt = 154pb-1 • Data taking period April 2002 – September 2003 • Dimuon data sample ~20M events (~4% of all data) • Preselection • Any Dimuon trigger has fired • Veto against cosmic muons (Scintillator timings) • 2 muons with pt > 20 GeV, pt > 8 GeV • 2 jets with pt > 15 GeV, pt > 10 GeV • 2nd jet pt > 20 GeV OR 2nd muon pt > 20 GeV • central track match & isolation for both muons • dimuon angle ΔRμ1,μ2 > 1.0 to reject QCD events  258 events (270.5 ± 8.0[stat] ± 79.6[syst] expected) Bad Honnef, 6.-10. September 2004

  7. Control Plots of the Data Sample (1) Signal (red) is scaled up by a factor 10 Bad Honnef, 6.-10. September 2004

  8. Control Plots of the Data Sample (2) Signal (red) is scaled up by a factor 10 Bad Honnef, 6.-10. September 2004

  9. Dimuon Trigger Efficiency Weight all MC events according to muon (pt, η, φ), jet, MET to account for dimuon trigger inefficiencies Estimate systematic error by varying the correction factor by ±1 standard deviation Z/γ* Z/γ* Bad Honnef, 6.-10. September 2004

  10. εData = 81.7% εMC = 86.9% Isolation Efficiency SRC track cone core hollow cone Σ ET < Eiso i i pT η φ Bad Honnef, 6.-10. September 2004

  11. Cross sections from Pythia are LO. • weight Z-MC events with k(Mμμ) to account for higher order corrections Z/γ* Cross Section Z/γ* NNLO NNLO correction with CTEQ6 is used to weight the Z/γ* • References: • R. Hamberg et. al.: A COMPLETE CALCULATION OF THE ORDER ALPHA-S**2 • CORRECTION TO THE DRELL-YAN K FACTOR., Nucl.Phys.B359:343-405,1991 • K. Hagiwara et al., Particle Data Group, Phys. Rev. D 66, 010001 (2002) • T. Nunneman, D0 Note 4476 Mμμ Bad Honnef, 6.-10. September 2004

  12. Systematic Uncertainties Effect on the pre-selection sample • Jet Energy Scale uncertainty • is the dominating systematic error • (Two jets in the final state) • 6.5% – 30% uncertainty per jet • depending on jet pT, η,φ • jet 1 pT > 25 GeV • jet 2 pT > 15 GeV • jet 2 pT > 20 GeV || muon 2 pT > 20 GeV Bad Honnef, 6.-10. September 2004

  13. Invariant mass of • 2 jets and the lower • energetic muon • muon is from -decay • muon is from μ-decay • neither nor ~ ~ Signal MonteCarlo (SUSYGEN) Invariant mass of 2 jets and 2 muons Generated with Susygen and passed through full detector simulation & reconstruction. ~ mass  = 102 GeV mass μ = 262 GeV 0 1 ~ Bad Honnef, 6.-10. September 2004

  14. Final Selection • cut range . • pT (μ1) > 21.25 GeV + 0.188 (Mμ - M) • pT (μ1)+pT (μ2) > 60 GeV • pT(jet1) > 25 GeV • π – 1 < Δφ (μ1,jeti) < π + 1 • 0.5 < Δφ (μ2,jeti) < 2.5 • 91 GeV–(5 GeV+M/9) < Mμμ< 91 GeV+(5 GeV+M/9) • M – 40 GeV < Mμ2,jet1,jet2 < M+ 20 GeV • Mμ – 0.2·Mμ < Mμ1,μ2,jet1,jet2 < Mμ + 0.2·Mμ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Bad Honnef, 6.-10. September 2004

  15. Signal Efficiencies Constant slepton mass (200, 300 GeV) Constant neutralino mass (75, 100 GeV) The neutralino decays only with ~50% BR into two muons and two jets. Bad Honnef, 6.-10. September 2004

  16. Signal Region (m=102GeV, mμ=263GeV) ~ ~ 1 Reconstructed smuon mass (Inv. mass of muon1, muon2, jet1 & jet2) Invariant dimuon mass After all cuts for this mSUGRA point: 1.1±0.3±0.2 SM evts expected 2 data events found (4.4±0.5±0.8 signal events) Cut to remove the remaining Z0 background • good agreement between data and standard model background Bad Honnef, 6.-10. September 2004

  17. Cross Section Limits Control plots for this point Bad Honnef, 6.-10. September 2004

  18. Cross Section Limits Bad Honnef, 6.-10. September 2004

  19. Limits on LQD coupling λ’211 Control plots this point Theoretical Limit from lepton universality in the pion decay Bad Honnef, 6.-10. September 2004

  20. Limits on LQD coupling λ’211 Bad Honnef, 6.-10. September 2004

  21. Conclusions • Search for RPV SUSY through the LQD coupling λ’211 in the two muons plus two jets final state • Data agrees well with Standard Model expectation • Exclusion limits with 95% CL have been presented, improving on Run I results • Already 0.5 fb-1 data on tape: ≈ 3 times more than used for this analyses • Presented at ICHEP and DPF • Conference Note 4535 with more detailed information is available at http://www-d0.fnal.gov/Run2Physics/WWW/results/NP/np.htm • Improve analysis by • using more luminosity • adding the neutralino (missing ET) channel • Better signal selection Bad Honnef, 6.-10. September 2004

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