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Klaus Desch, Tatsiana Klimkovich, Thorsten Kuhl, Alexei Raspereza University of Hamburg/DESY

SUSY Higgs Pair Production at LC 500/800/1000. Klaus Desch, Tatsiana Klimkovich, Thorsten Kuhl, Alexei Raspereza University of Hamburg/DESY ALCPG meeting - SLAC 09/01/04. Motivation. Detection of heavy neutral Higgs Bosons difficult at LHC in parts of parameter space

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Klaus Desch, Tatsiana Klimkovich, Thorsten Kuhl, Alexei Raspereza University of Hamburg/DESY

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  1. SUSY Higgs Pair Production at LC 500/800/1000 Klaus Desch, Tatsiana Klimkovich, Thorsten Kuhl, Alexei Raspereza University of Hamburg/DESY ALCPG meeting - SLAC 09/01/04 Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  2. Motivation • Detection of heavy neutral Higgs Bosonsdifficult at LHC in parts of parameter space • Important to disentangle structure of • Higgs sector (2HDM, more singlets etc?) • Heavy Higgs sector helps a lot in the determination of SUSY parameters • (e.g. sensitivity to tanβ, see Gunion et al) • No detailed experimental study so far. • Questions: • Which decay modes can be measured ? • Precision on rate (for which √s, L,…) ? • Precision on massses ? Mass splitting ? • Distinguish H and A ? • Can the decay width be measured ? • CP violation ? (mixtures) Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  3. Simulation • PYTHIA for signal + background generation • CIRCE for beamstrahlung • SIMDET for fast (TESLA) detector simulation • b tagging with ZVTOP based ANN • basic tau ID • kinematic fits (DELPHI package) • Study a grid of A/H masses for • 500 fb-1 at √s=500 GeV, 800 GeV (and 1 point at 1 TeV) • Signal cross section: σ(HA) = sin2(β-α) λσSM(HZ) • We assume sin2(β-α) = 1 and • BR(H/Abb) = 0.9, BR(H/Aττ) = 0.1 Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  4. Signal grid note: in decoupling limit CP conserving MSSM, normally mA≈mH but large Δm may appear e.g. if CP violation is present Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  5. Backgrounds rather complete SM BG sample: o(30 M) events in total Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  6. Selection Strategy HA bbbb: • cut based selection using • event shape • jet btags • kinematic fit (4C) • 3 di-jet combinations (take them all) • reconstruct ΣM and ΔM • Efficiency ~40% Accepted background ~4/1 fb (500/800 GeV) HA bbττ: • likelihood selection using • 4 jet events (2b and 2τ) • τjets: low multiplicity (1 or 3 tracks) • LH: event shape + b tags • kinematic fit (assuming tau-jet direction = tau direction) • reconstruct ττ mass and bb mass • Efficiency ~30-45% Accepted background ~2-6 fb Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  7. Results: bbbb Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  8. Results: bbττ allows for relative BR determination of the two Higgses individually! Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  9. Results bbττ: mass degenerate case Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  10. Results Precision on rate: Precision on mass: precise 5σ discovery reach to be determined ~ √s/2 – 50 GeV for bbττhigher for bbbb (for mass-deg. case) Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  11. SPS1a Results Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  12. Decay Width Measurement? Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  13. Decay Width Measurement? Klaus Desch, SUSY Higgs Pair Production, 09/01/04

  14. Summary + Conclusions • Experimental study of heavy SUSY Higgs bosons: LC note ready this month • Rates for bbbb and bbττ can be measured with % level accuracy • Masses can be measured to o(1 GeV) precision up to few tens of GeV below kinematic limit • First attempt to measure total width (lineshape) resolution ~few GeV if enough rate from bbττ • H/A of SPS1a can be measured at 1 TeV machine • (can be used as input to overall SUSY parameter fits) • Also non mass-degenerate case studied • (can be used as input to CP violation studies) • To be done: SUSY decays, interpretation in SUSY models Klaus Desch, SUSY Higgs Pair Production, 09/01/04

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