# Presentation: 168296

## Top and Electroweak Results from CDF

*Igor Volobouev*
*LBNL*
* **for the CDF Collaboration *

## Top / Electroweak Program

- Measurement of fundamental parameters
- Calibration (*e.g*., MZ )
- Precision measurements of Mtop, MW, Vtb, *etc*.
- Tests of Standard Model predictions
- Cross sections, branching fractions, kinematical distributions, lepton universality
- Top quark properties: unique to CDF/D0
- Searches for new phenomena
- Higgs
- Anomalous couplings, new particles and resonances, rare and forbidden decays
- Discovery potential exists in all areas

## CDF Run 2 Upgrade

- Improved Si coverage
- || < 2
- up to 8 layers
- New central tracker
- 96 layers
- Time of Flight
- Expanded muon system
- Forward calorimeter
- Trigger and electronics

****** ****= -ln(tan(********/2))**

## Run 2 Data Sample

- Total current sample on tape: 175 pb-1
- “Winter analyses” sample: 56-91pb-1
- 4-9 pb-1/week
- 90% efficiency

- “Winter” sample

- Commissioning

**Delivered**

**On Tape**

- Store Number

- Total Luminosity (pb-1)

## Electroweak Measurements

- Unambiguous predictions from the Standard Model, world averages, Run 1 measurements
- W, Z production cross sections
- Lepton universality
- Forward-backward asymmetry
- Di-boson production
- “New physics” reach at a few hundred pb-1
- Data analysis infrastructure
- Lepton and photon identification
- W and Z signatures
- Calibrations
- Luminosity monitoring

## B(Wll)

|  | Events | Background | •B(Wll) (nb) |
| --- | --- | --- | --- |
| e | 38625 | 6% | 2.64±0.01stat±0.09sys±0.16lum |
|  | 21599 | 11% | 2.64±0.02stat±0.12sys±0.16lum |

- Clean signature
- Isolated lepton
- Missing ET
- High  and S/B
- 72 pb-1

- W

## Wand Lepton Universality

- Narrow, isolated hadronic jet from 
- Missing ET > 25 GeV
- Electrons removed
- Relatively low background ( 26%)

- **B(W************) =**** **
**2.62 ± 0.07****stat ****± 0.21****sys ****± 0.16****lum**** nb**** **

## B(Zll)

- B(Zll)

- Two leptons: negligible background (< 1%)
- Used for calibrations: energy scale, resolutions

**l ****=e:  267**±6stat±15sys±16lum pb
**l ****=********:  246**±6stat±12sys±15lum pb

## AFB with Z0/*  e+e-

- Forward-backward asymmetry:

- Probes /Z interference, sensitive to new physics
- High mass reach is unique to Tevatron
- Measurement is consistent with the SM prediction

## pp  W, Z, WW
Depend on trilinear gauge couplings (s-channel):

Events found expected 
  W
   Z
  WW     4.3
Results are statistics-limited, consistent with the SM predictions

- pp  W, Z, WW
- Depend on trilinear gauge couplings (s-channel):
- Events found expected
-   W
-    Z
-   WW     4.3
- Results are statistics-limited, consistent with the SM predictions

- Di-boson Cross Sections

- 81 events

## Top Quark Measurements

- Main question: is top quark adequately described by the Standard Model?
- Run 2 results so far:
- Cross section
- Top mass
- Many precision tests of top to come with more data
- SM: tt production cross section at 1.96 TeV is 30% larger than at 1.8 TeV

## Dilepton Cross Section

- Signature: 2 leptons, 2 jets, missing ET
- Backgrounds: WW, Z  , Drell-Yan, fake leptons
- Event selection: signature and
- Scalar transverse energy > 200 GeV
- Background rejection: photon conversion veto, Z veto, lepton isolation,  for missing ET
- Found 5 candidates, expected 0.3 background events

## Lepton + Jets Cross Section

- Control

- Signal

- 15 candidate events with b tags, 3.8 background

## Lepton + Jets Cross Section

- Control

- Signal

- 15 candidate events with b tags, 3.8 background

## tt  Cross Section Summary

- tt  Cross Section Summary

- hep-ph/0303085 (M. Cacciari et al)

## Top Quark Mass

- Lepton + jets channel: Run 1 CDF result was
-      176.1 ± 6.6 GeV/c2
- Statistical error is mainly due to jet combinatorics. Mtop with b tags will be presented at the summer conferences.
- Systematic errors will dominate the uncertainty
- Jet energy reconstruction
- MC top decay modeling
- Background

- 33 events

## Future Run 2 Measurements

- Electroweak
- Drell-Yan at high mass (PDFs, new physics)
- W charge asymmetry
- Direct W width
- pp  WZ, ZZ, trilinear couplings
- MW with 40 MeV/c2 precision (400 pb-1 are needed if 1/L scaling holds)

- Top
- Analysis of production and decay kinematics
- Resonant production
- W helicity
- Spin correlations
- Single top production
- Vtb
- Rare and forbidden decays
- Mt with 3 GeV/c2 precision

- Many of these measurements are already in the works

## Higgs Constraint

- Current SM Higgs fit: MH = 81+52–33 GeV
- LEP 2 direct search limit: MH > 114.4 GeV at 95% CL

## Summary

- A variety of Run 1 results have been reestablished
- We are confident that CDF components are working as expected and the system integration was a success
- Our understanding of the CDF detector is improving. We have already developed many building blocks needed for taking on really challenging physics problems.
- So far, top and electroweak results are consistent with the Standard Model predictions
- Most measurements are statistics limited, and will benefit from larger datasets
- Expect many new and improved Run 2 results this summer and during the next few years

## Backup Slides

## Electron Identification

- CEM transverse energy ET > 20 GeV
- Track pT > 10 GeV/c
- Track |z0| < 60 cm
- ET/pT < 2.0 when ET < 50 GeV
- Cluster EHAD/EEM < 0.055 + 0.00045 * E
- Track-to-shower match  3 cm
- Fractional calorimeter energy isolation <  0.1
- Shower profile consistent with electron
- Fiducial to CES

## Muon Identification

- Track pT > 20 GeV/c
- Track |z0| < 60 cm
- Cosmic ray veto
- EEM   <  2 + max(0, 0.0115 * (p - 100))  GeV
- EHAD <  6 + max(0, 0.0280 * (p - 100))  GeV
- Fractional calorimeter energy isolation <  0.1
- Track match to a muon chamber stub: 3, 5, and 6 cm for CMU, CMP, and CMX, respectively

## B Jet Tagging with SVX

- At least two well-reconstructed tracks with  3 silicon hits
- Secondary vertex LXY significance at least +3
- Efficiency in tt events: 45  1  5 %  for “taggable” jets

## Weekly Delivered Luminosity

## Downtime and Deadtime

- Downtime – much better when we keep taking data...
- HV Trips (COT, Silicon, muon, etc.) (not so often these days)
- L3/EVB/CSL/L2, etc. (comes/goes in wave.  Right now, it is good)
- HRRs (bunch counter errors, TDC done timeout, etc.)
- Trigger table tests, 2 SRC tests, XFT tests... (future investment)
- Startup time, waiting to bring up HV at beginning of the store
- Silicon D-mode calibration and other odds and ends
- Downtime due to operator errors are very small
- Dead time – much easier when lumi is low and trigger rates low, but...
- L1/L2 busy dead time (much work in progress, eg. 2SRC readout)
- Hitting CSL output limit -- design 20Mb/sec.  This current problem should be solved by:
- Tightening (wisely) trigger filters, limiting L3 output rates
- Dropping L3 reconstruction banks and other diagnostic banks
- Compressing silicon/COT raw data banks, etc.
- However, at the same time, we are also reviewing/studying the possibility/consequence of extending the current CSL 20Mb/sec limit

## Di-boson Run 2 Results

- WW: expected 2.8 signal and 1.5 background events (SM), found 2