# Presentation: 930597

## Top Dilepton Cross-Section in the Lepton+Track Sample:

**Supplementary Information**
**Joe Incandela, Petra Merkel, Corrinne Mills, Pierre Savard, Teresa Spreitzer, Julia Thom, Peter Wittich**

## W and Z: Validate Selection

- Z checks tight lepton, track lepton (= “tl”) selection
- W checks tight lepton and missing transverse energy
- W cross-sections are background-subtracted
- Uncertainties quoted are statistical only
- systematic uncertainties (estimated  5-10%) predominantly from lepton identification and background estimates

| CDF Run II Preliminary 360 pb-1 |  |
| --- | --- |
| Type |  (pb) |
| CEM-tl | 260 ± 3 |
| CMUP-tl | 237 ± 4 |
| CMX-tl | 260 ± 3 |
| PHX-tl | 260 ± 3 |

| CDF Run II Preliminary 360 pb-1 |  |
| --- | --- |
| Type |  (pb) |
| CEM | 2620 ± 6 |
| CMUP | 2756 ± 9 |
| CMX | 2677 ± 11 |
| PHX | 2515 ± 8 |

## Fake Rates

- Compare among the different jet samples:

**Notes: **
*“**Jet50” is data triggered by 50 GeV jets, used to construct the fake rate*
* **Use Jet50 to ****predict the number of observed fake leptons**** in other samples triggered by similar criteria*
* ****Systematic uncertainty**** on fakes accounts for observed discrepancies between jet samples*
* **Authors will ****work on improving this**** for 1 fb**-1*

|  |  | CDF Run II Preliminary 360 pb-1 |  |  |
| --- | --- | --- | --- | --- |
| Lepton | Avg. Fake Rate | Sample | Expected | Observed |
| isolated track | 2.6 x 10-3 | Jet 20  | 2070 ± 180 | 2170 |
|  |  | Jet 70 | 1950 ± 170 | 2410 |
|  |  | Jet 100 | 3950 ± 320 | 6110 |
| CEM | 7.6 x 10-5 | Jet 20  | 80 ± 30 | 40 |
|  |  | Jet 70 | 80 ± 30 | 30 |
|  |  | Jet 100 | 130 ± 40 | 80 |
| CMUP | 1.5 x 10-5 | Jet 20  | 14 ± 6 | 12 |
|  |  | Jet 70 | 14 ± 6 | 10 |
|  |  | Jet 100 | 24 ± 10 | 80 |
| CMX | 0.6 x 10-5 | Jet 20  | 6 ± 2 | 3 |
|  |  | Jet 70 | 6 ± 2 | 3 |
|  |  | Jet 100 | 9 ± 4 | 13 |
| PHX | 11.8 x 10-5 | Jet 20  | 120 ± 40 | 90 |
|  |  | Jet 70 | 70 ± 20 | 100 |
|  |  | Jet 100 | 120 ± 40 | 160 |

## Fake Rates

- Graphical representation of table on previous page

**Notes: **
*“**Jet50” is data triggered by 50 GeV jets, used to construct the fake rate*
* **Use Jet50 to ****predict the number of observed fake leptons**** in other samples triggered by similar criteria*
* ****Systematic uncertainty**** on fakes accounts for observed discrepancies between jet samples*
* **Authors will ****work on improving this**** for 1 fb**-1*

## Systematic Uncertainties

| CDF Run II Preliminary 360 pb-1 |  |
| --- | --- |
| Signal Systematic Uncertainties |  |
| Source  | Uncertainty |
| tight lepton ID efficiency | 4 % |
| track lepton ID efficiency | 3 % |
| jet energy scale | 2 % |
| initial state radiation | 3 % |
| final state radiation | 3 % |
| PDF | 0.4 % |

| CDF Run II Preliminary 360 pb-1 |  |  |
| --- | --- | --- |
| Background Systematic Uncertainties |  |  |
| Source | Uncertainty on Background  | Uncertainty on cross-section  |
| tight lepton ID efficiency | 4 % | 0.5 % |
| track lepton ID efficiency | 3 % | 0.4 % |
| jet energy scale | 11 % | 1.4 % |
| MC generator | 13 % | 0.2 % |
| Drell-Yan ee and  | 50 % | 10.5 % |
| fakes estimate | 30 % | 3.8 % |

## Cross-checks: Tight-Tight

- Require track lepton to match a tight lepton in 
- Based on track lepton pT > 20 GeV, jet ET > 20 GeV analysis
- Higher purity sample (S/B  3, in main analysis is  1.)
- Systematic uncertainties similar to main analysis

## Cross-section at Different MT

| CDF Run II Preliminary 360 pb-1 |  |  |
| --- | --- | --- |
| MT (GeV/c2) | theory (pb) | measured  (pb) |
| 165 | 9.0-1.1+1.0 | 11.1 ± 2.4 ± 1.5 ± 0.7 |
| 170 | 7.8-1.0+0.9 | 10.7 ± 2.3 ± 1.4 ± 0.6 |
| 175 | 6.7-0.9+0.7 | 10.1 ± 2.2 ± 1.3 ± 0.6 |
| 178 | 6.1-0.8+0.6 | 9.9 ± 2.1 ± 1.3 ± 0.6 |
| 180 | 5.8-0.8+0.6 | 9.7 ± 2.1 ± 1.3 ± 0.6 |

## Event Display: An e- 3-jet event

- MET:
- 68 GeV,  = 5.4

- tl (= CMX muon):
- pT = 35 GeV,
-  = 0.4

- CEM electron:
- ET = 34 GeV,
-  = 5.3

- Jet 1: ET = 67 GeV

- Jet 3:
- ET = 23 GeV

- Jet 2:
- ET = 27 GeV

***CDF Run II Preliminary (360 pb******-1******)***

## A double-tagged e-event

***CDF Run II Preliminary (360 pb******-1******)***

- MET: 91 GeV,  = 2.8

- CEM electron:
- ET = 61 GeV,
-  = 4.8

- tl (= CMX muon):
- pT = 102 GeV,
-  = 0.8

- Jet 1:
- ET = 43 GeV,
*tagged*

- Jet 2:
- ET = 37 GeV,
*tagged*

- Jet 3:
- ET = 36 GeV