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SUSY point5/Tau-pair full simulation study

SUSY point5/Tau-pair full simulation study. Taikan Suehara ICEPP, The Univ. of Tokyo. Analysis notes. Tau-pair http://www.ilcild.org/documents/ild-loi-material/tau090316.pdf/at_download/file SUSY point5 http://www.ilcild.org/documents/ild-loi-material/point5_090319_2.pdf/at_download/file

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SUSY point5/Tau-pair full simulation study

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  1. SUSY point5/Tau-pairfull simulation study Taikan Suehara ICEPP, The Univ. of Tokyo

  2. Analysis notes • Tau-pair http://www.ilcild.org/documents/ild-loi-material/tau090316.pdf/at_download/file • SUSY point5 http://www.ilcild.org/documents/ild-loi-material/point5_090319_2.pdf/at_download/file To be published??

  3. Tau-pair analysis

  4. Tau-pair process Difficulty on decay analysis [Observables] P(e-)=80%, P(e+)=30%, 500 fb-1 • σ, AFB(bg suppression) • Polarization P(t)↑Decay angle determination σ=2600 fb-1 (e-Le+R)σ=2000 fb-1 (e-Re+L) radiative events: ~70%

  5. BG suppression BG suppression cuts • # Track<=6 • 1(+)+1(-) clusters • Opening angle >178deg • |cosq|t < 0.9 • < 2 electrons, < 2 muons • 40 < Evis < 450 GeV • 30 < MaxE(t) < 240 GeV Purity ~ 90% (almostbg free)

  6. Cut plots

  7. σ, AFB σ: 0.33% (e-Le+R), 0.37% (e-Re+L) stat. error(count based) AFB: 51.64 ± 0.29% (e-Le+R), 44.18 ± 0.37% (e-Re+L)

  8. Decay modes in Apol analysis 5 major decay modes • Leptonic(35.3% in total) • 「Lepton ID」(high eff.) • P=0.22 (lost power by 2 ns) • Pinudecay(10.8%) • 「only one p±」(simplest) • P=0.58 (full) • Rhonu decay(23.7%) • 「one p±+2g」　P=0.49 (almost full) • A1nu decay(12.9%) • 「one p±+4γ」or「three p±」(each 50%) • P=0.45, 3-prongis useful. Branching ratio of tau P = analyzing power M.Davier et al., PLB306 411 (1993) Minimize stat. error by combining decaymodes

  9. r, a1 and p0 reconstruction • Lepton ID • # Particle(charged neutral) • Invariant mass Decay mode separation by various information

  10. Mode selection (1) Leptonic mode Pinu mode

  11. Mode selection (2) Rhonu mode

  12. Mode selection (3) A1 mode (3prong)

  13. Apol calculation (pn mode) left right Reco dist with all cuts MC truth with minimal cuts

  14. Apol calculation (pn mode) (cont.) ± ±

  15. Estimation using analyzing power • Pinu: 1.5% stat. error • Analyzing power is 4.5 times larger if usingall modes • Total stat. error estimation = 0.7%

  16. SUSY jet analysis

  17. SUSY chi1/ne2-pair process BG suppression cuts “qqqq + missing” • 4-jet clustering (Durham) • # Track>=20 • 100 < Evis < 300 GeV • each Ejet > 5GeV • |cosq|jet < 0.99 • unlike 3jet(yth,3 > 0.001) • each jet has >= 2tracks • |cosq|miss < 0.99 • no > 25 GeVleptons SUSY parameters: m0 = 206 GeV, m1/2 = 293 GeV, tan b = 10, A = 0, m = 375 GeV m(c±1) = 216.5 GeV, m(c02) = 216.7 GeV m(c01) = 115.7 GeV, Others heavy s(e+e-→c+1c-1) = 132.2 fb s(e+e-→c02c02) = 23.3 fb Degenerate 100 GeVdiff.: decays W/Z+ LSP(>95%) Loose cut (efficiency ~ 90%) 5.7 times

  18. Cut plots(1)

  19. Cut plots(2)

  20. Cut statistics

  21. W/Z mass dist. & kinematic fit Di-jet mass: 4-momenta Jetの相対角 qqqq → 2 jet pairing Kinematic fit • 3 patterns(12&34,13&24,14&23) • All combinations • Best combination • - Combination near W/Z mass • - Kinematic fitconvergence Adjust jet energy/directionfor di-jet masses are the same Observables 1. Cross section - all combinations 2. Mass measurement - Kinematic fit - Best combination (W/Zmassfor cut, kinfit conv. for pairing)

  22. Cross section measurement ↑SM background c±: 0.64% resolution c0 : 2.1% resolution ↑all events ↓c± template ↓c0 template ↓Fit result

  23. Mass fitprocedures Procedure • Kinematic fit • W/Z separation withdi-jet mass • 　→upper plots • SM backgroundparametrization • 2nd polynomialx Voigt • 　→left plot

  24. Mass fit result Procedure (cont.) Fitresult m(c±1) = 221.7 ± 2.4 GeV m(c02) = 219.9 ± 0.9 GeV m(c01) = 118.5 ± 0.8 GeV SMdist. by toy-MC SUSY+SMfit(8 free param.)Convolution of 2nd pol.& Voigtfunc. + SM(fixed)integration range of convolutionexpresses edges. Mass by kinematics • Edge fitsystematics exist • Much SM bg

  25. Summary • Tau-pair • Enough cross section / AFB resolution • ~70%efficiency/purityfor decay mode selection • 1.5% (pinu), 0.7% (combined) stat. errorfor polarization determination (500 fb-1) • SUSY point5 • Separation W/Z is promissing • 1-2GeVSUSY mass determination

  26. The end

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