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Overview

Overview. Search for RPV Susy through the LQD coupling λ ’ 211 Christian Autermann III. Physikalisches Institut A RWTH Aachen. R-parity violating Supersymmetry Cross section and Run I Limit Data Selection & Efficiencies Control plots First Results. R-parity Violating Supersymmetry.

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Overview

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  1. Overview Search for RPV Susy through the LQD coupling λ’211 Christian Autermann III. Physikalisches Institut A RWTH Aachen • R-parity violating Supersymmetry • Cross section and Run I Limit • Data Selection & Efficiencies • Control plots • First Results Christian Autermann - Resonant Slepton Production

  2. R-parity Violating Supersymmetry Assuming a non-zero λ`211 coupling, leads to muon (2nd gen.) and two jets (1st gen.) final states. tri-lepton channel, Anne-Marie, Daniela i,j,k = 1,2,3 generation indices Chiral superfields: L: lepton doublet superfield Q: quark doublet superfield D: down-like quark singlet superfield λ, λ`, λ``: Yukawa couplings Resonant production ! 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 Christian Autermann - Resonant Slepton Production

  3. production decay Neutralino Production & Decay Final state: two (isolated) muons two jets • Other modes: • sneutrino resonance  2 jets, MET & perh. 1 μ • neutralino pair production and decay over λ`211 • t-channel slepton exchange Christian Autermann - Resonant Slepton Production

  4. Slepton Production x-section Run I slepton production cross section: 3.34 pb (SUSYGEN, λ’211=0.09, mslepton=269GeV) For λ’211=0.09, mslepton=269GeV and : σ=2.96 pb : σ=3.47 pb Susygen with Suspect interface had a bug in older versions: ( ) σ: SUSYGEN 3.00/16: 6.8 pb (SUSPECT) σ=10.59 pb σ:SUSYGEN 3.00/43: 2.24 pb (SUSPECT)  σ= 3.49 pb Christian Autermann - Resonant Slepton Production

  5. Exclusion Contour DØ Run I mSUGRA parameters m0 universal soft breaking mass parameter for scalars m1/2 universal soft braking mass parameter for gauginos A0 trilinear coupling term sign(μ) higgs mass mixing parameter tan(β) ratio of the vacuum expectation of the neutral higgs fields m0, m1/2 and A0 are defined at the GUT scale This talk DØ Collaboration, Phys.Rev.Letter 89 (2002), hep-ex/0111053 Christian Autermann - Resonant Slepton Production

  6. Data Sample & Preselection • Total delivered L=209pb-1, good & reconstructed L=154pb-1. • Data taking period April 2002 – September 2003 • Di-muon data sample, ~4% of all data • Re-skim (6% of di-muon sample, 297k events): • 2 muons with pt>5 GeV and pt>3 GeV and a good central track match • Anti cosmic cuts |t_A|<10ns, -15ns<|t_B|<10ns • 2 jets with each pt>10 GeV and |eta|<2.5 • Preselection • Di-muon trigger has fired [2MU_A_L2M0 || 2MU_A_L2M0_TRK5 || 2MU_A_L2M0_TRK10 || 2MU_A_L2M0_L3L6 || 2 MU_A_L2M0_L3L15] • good/bad run selection • central track match & isolation for both muons • 1 muon pt>20 GeV, 1 muon pt>8 GeV • 1 jet pt>20 GeV, 1 jet pt>15 GeV • di-muon angle ΔRmu1,mu2>1.0 to reject QCD events  645 events Christian Autermann - Resonant Slepton Production

  7. Isolation Efficiency SRC track cone core hollow cone Σ ET < Eiso i i εData = 81.7% εMC = 86.9% εData = 0.942 ·εMC Christian Autermann - Resonant Slepton Production

  8. Di-Muon Trigger Efficiency TriggerEfficiency Class (Brigitte Vachon, top group) Weight all MC events with respect to muon, jet, MET and data luminosity so that all di-muon trigger inefficiencies are described. pT of 2. muon [GeV] Christian Autermann - Resonant Slepton Production

  9. x-sections from Pythia is only LO. The “k factor” is a common correction.  weight Z-MC events with k(Mμμ) k factor 1 1.1 1.2 1.3 1 10 102 103 μ [GeV] additional correction • 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) Christian Autermann - Resonant Slepton Production

  10. Control Plots of the Data Sample (1) PT for the most energetic muon Invariant di-muon mass Christian Autermann - Resonant Slepton Production

  11. Control Plots of the Data Sample (2) PT for the most energetic jet Inv. mass of muon1, muon2, jet1 & jet2 After pre-selection & corrections: 485 data events 487 background events expected 42.6 signal events expected Christian Autermann - Resonant Slepton Production

  12. Invariant mass of • 2 jets and the lower • energetic muon • muon is from -decay • muon is from μ-decay • neither nor ~ ~ ~ mass  = 102 GeV mass μ = 262 GeV 0 1 ~ Signal MonteCarlo (SUSYGEN) Invariant mass of 2 jets and 2 muons Generated with Susygen and passed through full detector simulation & reconstruction. Christian Autermann - Resonant Slepton Production

  13. Final Cuts 1 ~ Christian Autermann - Resonant Slepton Production

  14. Signal Region (preliminary) Inv. di-muon mass Inv. mass of muon1, muon2, jet1 & jet2 4.2 events expected 3 data events found (12.4 signal events) Final cut to remove the remaining Z0 background • good agreement between data and standard model background! Christian Autermann - Resonant Slepton Production

  15. Conclusion And Plans • Preselected data agrees reasonable well with background described by Pythia Z/DY incl. MC. • In the final sample 5.4 background events are expected and 3 data events have been found. • Don’t reject QCD events by cutting on the angle between the two muons in the pre-selection • Scan Susy parameter space • Apply a more “sophisticated” final selection Christian Autermann - Resonant Slepton Production

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