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

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

Strict Cut Summary Reject multiply analyzed runs (p & r ) – (+ 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 (P t > 6 GeV) –|  track  cand  | < 0.2 QCD Trigger –JT_25TT_NG, JT_45TT, JT_65TT, JT_95TT, JT_125TT, JT_8TT, CJT5, min_bias, min_bias_NCU ×2 data reduction

D0JetInfo Building CalJet (baseline) –Standard quality cuts Trackjet –At least 2 tracks –Pt(1) > 1.0 GeV –Pt(others) > 0.5 GeV  R < 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 –|  R | < 0.7 –|  Z | < 1.5 cm 2VTX –Attached to TrackJet –Complex requirements Muon –|  R | < 0.5 –|  Z | < 1.5 cm MC information –2VTX |  R | < 0.5 |  Z | < 3 cm –Parent parton (Leading Order) |  R | < 1.0 |  Z | < 100 cm Ariel Schwartzman based code.

Data Skim Result (All JT Trig) [Entire Skim] All Data 1mutrk skim My skimTMBTree P ,912,1227,310,03665,508 43,803 P ,852,86322,961,909136,343 R ,728,0132,675,42920,014 Total 389,492,99832,947,374221, , , ,388

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

MC Status MC Request #Request type# Events Now 5931 b b QCD / c c b b QCD c c b b QCD c c ?? b b 100 inclusive 0 ?? b b 200 inclusive 0 ?? b b 300 inclusive 0 Requested 20,000 of each Big thanks to Drew Meyer of UTA for very helpful MC assistance MC Production foundered for many months. Statistics only available in the last month

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

MC Predictions (single jet) Technique: 1.Use QCD MC (Ptmin = 100 GeV) 2.Identify “Leading Order” associated parton 3.Apply cuts in RECO variables 4.Identify efficiency and purity for each type Note: “light” includes up, down, strange and gluons. Note: this is for all . Reducing to |  | < 0.5 will reduce cross section numbers by 1/3, but slightly increase efficiency.

MC Predictions (two jet or double tag)

d  /dp t “ Cross-Section” |  | < 0.5 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   Jet kinematics only JT_25TT_NG JT_45TT JT_65TT JT_95TT JT_125TT All jets with   Jet +  kinematics

Pt Dependence of Cut Loss (  Data)

Pt Dependence of Cut Loss (QCD Data)

Efficiencies  T Trigger Eff  PV Primary Vertex Eff  j Jet Eff    Eff f b  Frac b   (Pt > 4 GeV) f B  Frac B   (Pt > 4 GeV) L Luminosity  p t Pt bin width  b b cross-section  B BKD cross-section Jet +  (Pt > 4 GeV) b Jet +  (Pt > 4 GeV) b Jet Correlated

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

Primary Vertex Cut Event Retention Error bars RMS Pt Z(PV)  PV = ± Independent of Pt

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

Pt Dependence of log(2D DL Sig) Essentially Pt independent in MC

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

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

Effect of Including  -only Jets in log(2D DL sig)

Effect of  existence on log(2D DL sig)

Compare templates of log(2D DL sig)

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%

Fit to smoothed templates 4 gaussian 3 gaussian2 gaussian Bump in c template probably Unphysical. Under investigation.

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.) Fit to Smoothed Templates

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

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

Efficiency Detail Value TT Trigger Eff  PV Primary Vertex Eff ±   Eff jj Jet Eff 0.99 ± 0.01 fBfB Frac B   (Pt > 4 GeV) Pt dependent fbfb Frac b   (Pt > 4 GeV) Pt dependent Efficiency/Fraction Summary

 RECO Efficiency Geometry  system hole |  A Layer | < <  < 5.15 MC# RECO# MCEff % b c b c Thoughts:   system shouldn’t care if it’s in a jet? (High Pt punch through?)   track should care if it’s in a jet. Low tracking efficiency in jet  match should care if it’s in a jet. Lots of potential fakes. Not much information from  ID group on this topic. (But tracking eff ~ 82% gives total eff of 85.7  82 ~ 70.2%.

Heavy Flavor JES

Still To Do Double check  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

d  /dm“ Cross-Section” |  | < 0.5 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   Jet kinematics only Both jets with  Jet kinematics only At least one jet with   Jet +  kinematics JT_25TT_NG JT_45TT JT_65TT JT_95TT JT_125TT