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The Physics of Generations (Update) 11-Dec-03 Don Lincoln f

The Physics of Generations (Update) 11-Dec-03 Don Lincoln f. Fact: The multi-generational structure of the quark doublets requires explanation and could herald compositeness. Motivation. CDF: PRL 82 (1999) 2038.

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The Physics of Generations (Update) 11-Dec-03 Don Lincoln f

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  1. The PhysicsofGenerations (Update) 11-Dec-03 Don Lincoln f

  2. Fact: The multi-generational structure of the quark doublets requires explanation and could herald compositeness. Motivation CDF: PRL 82 (1999) 2038 Under hypothesis of compositeness, deviation from point-like behavior would likely manifest in third generation. Conclusion: g  bb may exhibit desired deviant behavior. Explore b quark dijet mass as a possible signature. • Problem • ~100:1 QCD:bb Solutions • m tagging • 2nd VTX tagging • Impact parameter Fit to CDF qQCD calculation

  3. Reject multiply analyzed runs (p13.05.00 & r13.06.01) 169514 - 170150 (+ others) Reject “bad” runs JET, MET, Muon, CFT, SMT, CAL Skim QCD to reduce data set (pt of high pt jet, in order to have < 40% deviation from lower trigger) Pt(25) > 40 GeV (Guess) Pt(45) > 70 GeV Pt(65) > 95 GeV Pt(95) > 130 GeV NP 1mutrk skim 1 MuonCandidate (medium) Nseg ≥ 1 Nwhits(A) ≥ 2 Nwhits(B+C) ≥ 3 Nshits(A) ≥ 1 Nshits(B+C) ≥ 1 1 Track (Pt > 6 GeV) | Df (track/m cand)| < 0.2 QCD Trigger JT_25TT_NG, JT_45TT, JT_65TT, JT_95TT, JT_125TT, JT_8TT, CJT5, min_bias, min_bias_NCU Strict Cut Summary ×2 data reduction

  4. CalJet (baseline) Standard quality cuts Trackjet At least 2 tracks Pt(1) > 1.0 GeV Pt(others) > 0.5 GeV DR < 0.5 MuonCandidate (tight) Pt > 4 GeV Associated track Nseg ≥ 3 Nwhits(A) ≥ 2 Nwhits(B+C) ≥ 3 Nshits(A) ≥ 1 Nshits(B+C) ≥ 1 Match to CalJet TrackJet | DR | < 0.7 | DZ | < 1.5 cm 2VTX Attached to TrackJet Complex requirements Muon | DR | < 0.5 | DZ | < 1.5 cm MC information 2VTX | DR | < 0.5 | DZ | < 3 cm Parent parton (Leading Order) | DR | < 1.0 | DZ | < 100 cm D0JetInfo Building Ariel Schwartzman based code.

  5. Data Skim Result (All JT Trig) [Entire Skim]

  6. Luminosity [pb-1] (“good” runs) With bad run removal.

  7. MC Status Requested 20,000 of each MC Production foundered for many months. Statistics only available in the last month Big thanks to Drew Meyer of UTA for very helpful MC assistance

  8. Long Term Goal: Use bb to Search for Exotics • Dijet bb mass might signal new physics • Tags: • m • Pros: Skim based on this, much work done • Cons: Poor efficiency, ptrel similar sig/bkd at high Pt, |hm| < 2.0, avoid ICD for Jet • 2VTX • Pros: Very high efficiency, some work done, 2D Decay Length Significance tag promising • Cons: No skim available, |hVTX| < 1.4, avoid ICD for Jet • First approach: jet + m inclusive, |hjet| < 0.5

  9. MC Predictions (single jet) • Technique: • Use QCD MC (Ptmin = 100 GeV) • Identify “Leading Order” associated parton • Apply cuts in RECO variables • Identify efficiency and purity for each type • Note: “light” includes up, down, strange and gluons. Note: this is for all h. Reducing to |h| < 0.5 will reduce cross section numbers by 1/3, but slightly increase efficiency.

  10. MC Predictions (two jet or double tag)

  11. ds/dpt “Cross-Section” |h| < 0.5 JT_25TT_NG JT_45TT JT_65TT JT_95TT JT_125TT All jets with m Jet kinematics only Obviously needs rebinning Normalized to luminosity and bin width Full luminosity “good runs” Uses standard JES No efficiency corrections No b-enhancing muon cuts All jets with m Jet + m kinematics

  12. Pt Dependence of Cut Loss (m Data)

  13. Pt Dependence of Cut Loss (QCD Data)

  14. eT Trigger Eff ePV Primary Vertex Eff ej Jet Eff emm Eff fbm Frac b  m(Pt > 4 GeV) fBm Frac B  m(Pt > 4 GeV) L Luminosity Dpt Pt bin width sb b cross-section sB BKD cross-section Efficiencies Correlated Jet + m (Pt > 4 GeV) b Jet + m (Pt > 4 GeV) b Jet

  15. Primary Vertex Cut Event Retention Respectable fit to a gaussian. Simply count events outside |z| > 50 cm to find loss rate.

  16. Primary Vertex Cut Event Retention +50 -50 ePV = 0.935 ± 0.050 Independent of Pt 100 300 700 Z(PV) Error bars RMS Pt

  17. Effect of Jet QC • Algorithm same as QCD analysis: • Find ratio (QC applied)/(QC not applied) • Correction = ½ difference • Error = ½ difference • eJ = 0.99 ± 0.01

  18. Pt Dependence of log(2D DL Sig) Essentially Pt independent in MC 3.65 2.75 2.5

  19. Effect of Jet Pt on log(2D DL sig)

  20. Pt Dependence of log(2D DL Sig) Essentially Pt independent in Data (Pt > 100)

  21. Effect of Including m-only Jets in log(2D DL sig)

  22. Effect of m existence on log(2D DL sig)

  23. Compare templates of log(2D DL sig)

  24. Compare templates of log(2D DL sig)

  25. Fractions of b using Templates For jets with both a good 2VTX and a muon, use log(2D dl sig) and fit for b fraction. Result: 15  2 and 22.6  2% MC: 24.4  1.5% w/o 2VTX requirement: MC: 10.5  0.4%

  26. Fit to smoothed templates 4 gaussian Bump in c template probably Unphysical. Under investigation. 3 gaussian 2 gaussian

  27. Fit to Smoothed Templates For jets with a good 2VTX use log(2D dl sig) and fit for b fraction. No muon requirement. Result: 16.7  1.2% MC: 26.2  0.8% Note: doesn’t have the same selection of events as data. (Even though no muon requirement, was a muon skim.)

  28. Fraction of b-generated Events with m Pt > 4.0 GeV Generate bb MC Calculate fraction of b  m (Pt > 4 GeV) Plot vs. Jet + m RECO Pt Fit Sys. Error. From adding parameter error. Frac = 0.045 + 0.000081 Pt

  29. Fraction of QCD-generated Events with m Pt > 4.0 GeV Generate QCD MC Calculate fraction of QCD  m (Pt > 4 GeV) Plot vs. Jet + m RECO Pt Fit Sys. Error. From adding parameter error. Frac = 1.0E-5 + 3.1E-6 Pt

  30. Efficiency/Fraction Summary

  31. Geometry m system hole |hA Layer| < 1.1 4.25 < f < 5.15 m RECO Efficiency • Thoughts: • e m system shouldn’t care if it’s in a jet? (High Pt punch through?) • e m track should care if it’s in a jet. Low tracking efficiency in jet • e match should care if it’s in a jet. Lots of potential fakes. Not much information from m ID group on this topic. (But tracking eff ~ 82% gives total eff of 85.782 ~ 70.2%.

  32. Heavy Flavor JES

  33. Heavy Flavor JES

  34. Still To Do • Double check m efficiencies • Double check fractions of b/c/light • Smearing  Resolution  Unsmearing • Rebin (How to deal with highest pt events?) • Bottom Line • Most required knowledge is grossly available

  35. ds/dm“Cross-Section” |h| < 0.5 Both jets with m Jet kinematics only At least one jet with m Jet kinematics only JT_25TT_NG JT_45TT JT_65TT JT_95TT JT_125TT Obviously needs rebinning Normalized to luminosity and bin width Full luminosity “good runs” Uses standard JES No efficiency corrections No b-enhancing muon cuts At least one jet with m Jet + m kinematics

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