22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production1 Overview R-parity violating Supersymmetry Cross section and Run I Limit Data Selection & Efficiencies Control plots First Results Search for RPV Susy through the LQD coupling λ’ 211 Christian Autermann III. Physikalisches Institut A RWTH Aachen

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production2 R-parity Violating Supersymmetry References: H. Dreiner, et.al., Search for R-Parity Violation at Run-II of the Tevatron, hep-ph/ hep-ph/ N.Ghodbane, S.Katsanevas, P.Morawitz, E.Perez, SUSYGEN 3, hep-ph/ hep-ph/ 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 ! Assuming a non-zero λ` 211 coupling, leads to muon (2 nd gen.) and two jets (1 st gen.) final states. tri-lepton channel, Anne-Marie, Daniela

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production3 Neutralino Production & Decay 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

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production4 Slepton Production x-section Run I slepton production cross section: 3.34 pb (SUSYGEN, λ’ 211 =0.09, m slepton =269GeV) 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 For λ’ 211 =0.09, m slepton =269GeV and : σ=2.96 pb : σ=3.47 pb

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production5 Exclusion Contour DØ Collaboration, Phys.Rev.Letter 89 (2002), hep-ex/ hep-ex/ This talk mSUGRA parameters m 0 universal soft breaking mass parameter for scalars m 1/2 universal soft braking mass parameter for gauginos A 0 trilinear coupling term sign(μ) higgs mass mixing parameter tan(β) ratio of the vacuum expectation of the neutral higgs fields m 0, m 1/2 and A 0 are defined at the GUT scale DØ Run I

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production6 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 ΔR mu1,mu2 >1.0 to reject QCD events  645 events

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production7 Isolation Efficiency ε Data = · ε MC ε Data = 81.7% ε MC = 86.9% cone core SRC track hollow cone Σ E T < E iso i i

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production8 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. p T of 2. muon [GeV]

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production9 μ [GeV] k factor x-sections from Pythia is only LO. The “k factor” is a common correction.  weight Z-MC events with k(M μμ ) 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: ,1991 K. Hagiwara et al., Particle Data Group, Phys. Rev. D 66, (2002)

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production10 Control Plots of the Data Sample (1) P T for the most energetic muonInvariant di-muon mass

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production11 Control Plots of the Data Sample (2) P T for the most energetic jetInv. mass of muon 1, muon 2, jet 1 & jet 2 After pre-selection & corrections: 485 data events 487 background events expected 42.6 signal events expected

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production12 Signal MonteCarlo (SUSYGEN) Invariant mass of 2 jets and 2 muons Invariant mass of 2 jets and the lower energetic muon muon is from  -decay muon is from μ-decay neither nor ~ ~ Generated with Susygen and passed through full detector simulation & reconstruction. mass  = 102 GeV mass μ = 262 GeV ~ ~ 0101

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production13 Final Cuts variablecut background rejection signal loss μ 1 p T 20 GeV  40 GeV27.6 %2.4 % μ 2 p T 8 GeV  10 GeV2.4 %2.0 % jet 1 p T 20 GeV  25 GeV20.4 %1.0 % M (μ 1, μ 2 )excl. Z 0 (76 GeV – 106 GeV)73.7 %27.5 % M (jet 1, jet 2 ) 30 < M < ∞ GeV 12.5 %3.4 % M (μ 1, jet 1, jet 2 )130 < M < 300 GeV46.5 %8.4 % M (μ 2, jet 1, jet 2 ) [  0 ] 70 < M < 130 GeV55.6 %16.2 % M (μ 1, μ 2, jet 1, jet 2 ) [μ]190 < M < 300 GeV58.3 %25.3 % total [relative to preselection]99.1 %70.5 % ~ 1

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production14 Signal Region (preliminary)  good agreement between data and standard model background! Inv. di-muon mass Inv. mass of muon 1, muon 2, jet 1 & jet 2 Final cut to remove the remaining Z 0 background 4.2 events expected 3 data events found (12.4 signal events)

22. April 2004, New Phenomena MeetingChristian Autermann - Resonant Slepton Production15 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