# Presentation: 692008

## The PhysicsofGenerations

- The PhysicsofGenerations
- (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  bb may exhibit desired deviant behavior.
- Explore b quark dijet mass as a possible signature.
- Problem
- ~100:1 QCD:bb
-             Solutions
-  tagging
- 2nd 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 (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)
- |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 skim | TMBTree |
| --- | --- | --- | --- | --- |
| P13.05 | 96,912,122 | 7,310,036 | 65,508 | 65,508
43,803  |
| P13.06 | 255,852,863 | 22,961,909 | 136,343 | 136,343 |
| R13.06 | 36,728,013 | 2,675,429 | 20,014 | 20,014 |
| Total | 389,492,998 | 32,947,374 | 221,168 | 221,251
193,822
100,388 |

## Luminosity [pb-1] (“good” runs)

- Luminosity [pb-1] (“good” runs)

**With bad run removal.**

## MC Status

| MC Request # | Request type | # Events Now |
| --- | --- | --- |
| 5931 | bb 100 | 31000 |
| 5932 | QCD 100 | 31000/24461 |
| 5933 | cc 100 | 20000 |
| 5934 | bb 300 | 40750 |
| 5935 | QCD 300 | 26500 |
| 5936 | cc 300 | 12500 |
| 5937 | bb 200 | 18500 |
| 5938 | QCD 200 | 46713 |
| 5939 | cc 200 | 41000 |
| ?? | bb 100 inclusive | 0 |
| ?? | bb 200 inclusive | 0 |
| ?? | bb 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 bb to Search for Exotics

- Dijet bb 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:
- 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 .  Reducing to || < 0.5 will reduce cross section numbers by 1/3, but slightly increase efficiency.

## MC Predictions (two jet or double tag)

## d/dpt “Cross-Section” || < 0.5

- d/dpt “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
- pt   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)

- +50

- -50

- 100

- 300

- 700

- PV = 0.935 ± 0.050
-   Independent of Pt

## Effect of Jet QC

- Algorithm same as QCD analysis:
- Find ratio (QC applied)/(QC not applied)
- Correction = 1⁄2 difference
- Error = 1⁄2 difference
***J* = 0.99 ± 0.01

## Pt Dependence of log(2D DL Sig)

- 3.65

- 2.75

- 2.5

- 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)

## 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 gaussian

- 2 gaussian

- Bump in c template probably
- Unphysical.  Under investigation.

## Fit to Smoothed Templates

- 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.)

## Fraction of b-generated Events with  Pt > 4.0 GeV

- Generate bb MC
- Calculate fraction of b   (Pt > 4 GeV)
- Plot vs. Jet +  RECO Pt
- Fit
- Sys. Error. From adding parameter error.

- Frac = 0.045 + 0.000081 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-5 + 3.1E-6 Pt

## Efficiency/Fraction Summary

| Efficiency | Detail | Value |
| --- | --- | --- |
| T | Trigger Eff | 1.000 |
| PV | Primary Vertex Eff | 0.935 ± 0.005 |
|  |  Eff |  |
| j | Jet Eff | 0.99 ± 0.01 |
| fB | Frac B   (Pt > 4 GeV) | Pt dependent |
| fb | Frac b   (Pt > 4 GeV) | Pt dependent |

##  RECO Efficiency

| MC | # RECO | # MC | Eff % |
| --- | --- | --- | --- |
| b100 | 2708 | 3907 | 69.3 |
| c100 | 853 | 1174 | 72.6 |
| b300 | 6561 | 9831 | 66.7 |
| c300 | 1098 | 1483 | 74.0 |

- 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

## 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