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PHD Work

PHD Work. J.E. Garcia. RTN – December 03. 2. Typical SCT beam test setup with different types of modules. Setup. Scintillator Trigger. Telescopes. Telescopes. 180 GeV pion Beam. Light tight, thermally insulating box. Modules inside the beam test box. J. E. Garcia.

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PHD Work

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  1. PHD Work J.E. Garcia RTN – December 03

  2. 2 Typical SCT beam test setup with different types of modules Setup Scintillator Trigger Telescopes Telescopes 180 GeV pion Beam Light tight, thermally insulating box Modules inside the beam test box. J. E. Garcia SCT Beam test results RTN – December 03

  3.  ~ 23 m • After 10 years the SCT will receive up to 2·1014 neq/cm2. Radiation causes damage on the module. • Radiation creates defects • Type inversion • Electronics noise and leakage current increase Variation of efficiency and noise occupancy with comparator threshold. Horizontal lines are the ATLAS specifications. Beam test studies 3 • Resolution is measured. SCT modules are almost single-strip. The detector pitch is 80 m in order to avoid charge sharing and preserve a good resolution. J. E. Garcia SCT Beam test results RTN – December 03

  4. S-Curve Beam test… (II) 4 • Signal to noise ratio for the SCT modules is  14. The pulse shape can be reconstructed from beam test data and compared with the theoretical response of the shaper • The median charge observed on binary SCT prototypes is around 3.4  0.2 fC • The Lorentz angle has been measured using a 1.56 T magnet and different incidence angles. The most sensitive parameter to these changes is the cluster size • L = 3.3 º  0.3 º (at 150 V) J. E. Garcia SCT Beam test results RTN – December 03

  5. efficiency Tracking study 5 SCT Modules Telescope • For reconstructing tracks only the position measurements of the irradiatedSCT modules are used. The beam telescope is only read out for comparison. Example of a reconstructed event • The tracking efficiency depends on threshold. The maximum efficiency is 97 % obtained at a threshold of 1.2 fC for a bias over 450 V. • Fake rate is kept below 10-3 independent of the bias voltage on the detector. J. E. Garcia SCT Beam test results RTN – December 03

  6. PHD Work J.E. Garcia RTN – December 03

  7. 7 • Littlest Higgs model • SU(5)  SO(5) • Gauge sector  [SU2U1]2 • Only 1 Higgs doublet • Arkani-Hamed et al., • JHEP 207 (2002) 34 • Phenomenology • Han et al., Phys. Rev. D67 (2003) 95004 • Burdman, Perelstein, Pierce, • hep-ph/0212228 M Particle Spectrum 0,+,++ T WH ,ZH AH 1 TeV t h Z ,W  scalar sector top sector gauge sector v’ ’ 1 new couplings Little Higgs Searches J. E. Garcia RTN – December 03

  8. q q’ ZH W q ZH T b q 8 ++ T Strategies at LHC q’ 1 q1 W+ ++ W+ q2 q’ 2 • VBF mechanism •  (v’)2 v’ should be small ++  W+W+ large SM bkg • Wb fusion •  (1)2 1  1 but suppressed by b-quark PDF. T bW, tZ clear signal qq annihilation   (cot)2 Wide range in cot possible. ZH e+e- clear signal Little Higgs Searches J. E. Garcia RTN – December 03

  9. l + l - b b b 9 l + ZH Zh with h bb l - Z Z ZH ZH 2 TeV 1 TeV h h b Cuts Cuts || < 2.5(jets and leptons) PT(Z) > 250 GeV PT(h) > 250 GeV b-tagging || < 2.5(jets and leptons) PT(Z) > 500 GeV PT(h) > 500 GeV b-tagging Background: Z + jets Little Higgs Searches J. E. Garcia RTN – December 03

  10. MZ = 1 TeV H L = 3·105 pb-1 cot  = 0.5 L = 3·105 pb-1 cot  = 0.5 10 MZ = 2 TeV H Signal and background Events Events M(ZH) (GeV) M(ZH) (GeV) b-tag: b = 40%, Ru = 100 Inside mass window: S = 15 S B = 8 B b-tag: b = 50%, Ru = 100 Inside mass window: S = 195 S B = 16 B = 5 = 50 Little Higgs Searches J. E. Garcia RTN – December 03

  11. 11 Discovery region ZH  Zh h(120)  bb L = 3·105 pb-1 S/B > 5 N > 10 ZH Zh l +l - bb WH Wh l  bb Little Higgs Searches J. E. Garcia RTN – December 03

  12. PHD Work J.E. Garcia RTN – December 03

  13. Z ZH q h 13 q ZH Zh   (cot  cot 2) 2 cot 2 cot  (cot ) • mh = 120 GeV • BR(h bb) = 66 % • BR(h ) = 0.2 % (cot  = 0.5) Ratio • mh = 200 GeV • BR(h W+W-) = 74 % • BR(h ZZ) = 26 % 0.5 Little Higgs Searches J. E. Garcia RTN – December 03

  14. MZ = 1 TeV MZ = 2 TeV H H 115 14 b-tagging < pT (bb)> = 800 GeV < pT (b)> = 220 GeV ~ 100 0.5 0.4 Little Higgs Searches J. E. Garcia RTN – December 03

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