# Presentation: 528056

## Measurement of W production at CDF 

**Measurement of W******** production at CDF **
**Naho Tanimoto, Okayama University, Japan**
**For the CDF Collaboration**

| Standard Model W signal |   98.9    1.5   (stat.)    5.6   (sys.) |
| --- | --- |
| QCD background |   28.1    0.1   (stat.)    9.4   (sys.) |
| Zbackground |   12.0    0.34 (stat.)    0.69 (sys.) |
| WW background |     1.74  0.16 (stat.)    0.14 (sys.) |
| Signal + Background | 140.7    1.6   (stat.)  11.0   (sys.)  6.8(lum.) |
| Data | 133 |

******(W********)********Br(W********l********)  =17.2 ******** 2.2 (stat.) ******** 2.0 (sys.) ******** 1.1 (lum.) [pb]**
******(W********)********Br(W********e********) =18.0 ******** 3.3 (stat.) ******** 2.5 (sys.) ******** 1.2 (lum.) [pb]**
******(W********)********Br(W********) =16.1 ******** 3.4 (stat.) ******** 1.7 (sys.) ******** 1.1 (lum.) [pb]**
**( E****T****(********) > 7 GeV and ********R(lepton,********)>0.7 )**

**Backgrounds to W********events**
-  QCD background : jet fakes to photon (67%)
-  ZZ ll : one lepton is misidentified (29%)
-  WWl (4%)

**Abstract**
**Diboson production provides a sensitive test of the Standard Model. We present an analysis of W+******** events, using 128 pb****-1**** of Run 2 CDF data, produced in pp collisions at the Tevatron with ********s=1.96TeV. Both electron and muon channels of the W boson are analyzed and compared to the Standard Model expectation.**

**1. Introduction**
- The Standard Model , W and Z gauge bosons are fundamental particles having no internal structure.The gauge symmetry for W and Z bosons severely constrains their couplings to each other. Measuring processes that are sensitive to these couplings provides a test of the gauge theory.

- At a pp collider, these processes can produce a W and  in the final state.

- Radiative W decay

**3. CDF Run2 Preliminary Results**
- The number of expected and observed events of W combining both electron and muon channels using integrated luminosity 128 pb-1. The major source of background is the misidentification of a jet as a photon.

**4. Conclusion**
- We measured W production cross section in ET() > 7 GeV and R(lepton, ) > 0.7 both electron and muon channels, and found it consistent with the Standard Model prediction.

-   : 36 GeV

-  : pT : 53 GeV

-  : ET=56 GeV

-  r- view of a W candidate

- Kinematical distributions of photon ET(up, left), R(lepton, ) (up, right), cluster transverse mass(down, right) and cluster transverse mass versus transverse mass(down, right)

-  s-channel decay

**2. Analysis**
**Event Selection**
- W selection
-  Isolated electron with ET>25GeV and ||<1.1
-  Isolated muon with PT> 20 GeV and ||<0.6
-  Large Missing ET>25(20 for ) GeV
-  selection
-  Isolated photon with ET 7GeV and ||<1.1
-  Quality cuts to reject 0 background
- W selection
-  Separation between lepton and photon, R(l)  0.7

**Theoretical prediction : ********(W********)********Br(W********l********)=18.6 ******** 1.3 (sys.) [pb]**
**( E****T****(********) > 7 GeV and ********R(lepton, ********) > 0.7 ) **

- Initial state radiation

- In the Standard Model, the trilinear gauge couplings,  =  - 1 and , are 0. If there is any deviation from the Standard Model, W cross section will be enhanced and the kinematical distributions are sensitive to anomalous couplings.

- The s-channel diagram contains the trilinear gauge couplings or vector boson self couplings,  and 

- Naho Tanimoto, Okayama University, 3-1-1 Tsushima-naka, Okayama, Japan

- Lepton-Photon 2003, Fermi National Accelerator Laboratory, Batavia, Illinois, USA, 11th-16th Aug. 2003