# Presentation: 325733

## Electroweak Physics

**Gauge Boson Interactions**
**W Boson Width**
**W Boson Mass**
**Top Quark Mass**
**Constraining the Higgs**

## Standard Model Gauge Boson Interactions

**Self-interactions are direct consequence of the non-Abelian SU(2)****L ****x U(1)****Y**** gauge symmetry.**
**Cancellation of t- and u-channel by  s-channel amplitude removes tree-level unitarity violation (W********, WW, and WZ). **

## Alternate Parameterizations

**LEP experiments started with 3 variables to parameterize WWV anomalous couplings.**

## Effect of non-SM Couplings

**Cross section increases especially for High E****T**** bosons (W/Z/********).**
**Unitarity Violation avoided. e.g.:**

- WW Production

-  is a form factor scale

- PT(W)

- (WW)

## D0 and LEP Combined

- 1 Limits
- g = = 0

- -0.16 < < 0.10   @95% CL

## Limits on Anomalous ZV Couplings

_**Limits on Anomalous ZV**__****__** Couplings**_

**Run I (ee,********)**
**+Run1a(********):**

- All at
- 95% CL

**Run Ib (ee,********)**

- 2D  Limits:

## Electroweak Boson Couplings Future

**Quantitative Expectations**
**Factor of 20X in luminosity provides ~ 2.5X improvement in T.G.C. limit. (at fixed form factor scale).**
**Numbers of events (CDF + D0) estimate.**
**W******** ****_****> l********                ~ 3000**
**Z******** ****_****> ee(********          ~ 700**
**WW ****_****> ll********             ~ 100**
**WZ ****_****> lll********               ~ 30**
**ZZ****_****> e’s and ********’s     a few**
**Qualitative Expectations**
**Wg and WZ radiation zero.**
**Probe theoretical expectations for T.G.C.’s.**

**ZZ  event CDF**

**WZ from D0**

## W Width

_**W Width**_

- Perturbative
- QCD

- LEP measurement

- SM EW

**W Width**

- SM Prediction ******W)=2.094   0.006GeV**

- 

##  W Boson Width

**SM: W ******** ************, *****qq***
**If additional non-SM particles exist which are lighter than and couple to the W boson**
****** ****additional contribution to the W boson width**
** ****Indirect measurements from the ratio of W and Z**
** ****cross sections:**

**DØ:  ********(W) = 2.107 ******** 0.054 GeV**

**Upper limit on non-SM decays of W**
******(W) ******** 132 MeV**** **

**CDF**** (NEW!): ********(W) = 2.179 ******** 0.040 GeV**

## W Mass Measurement Method

**m****T,****p****Tl**** used to measure M****W**
**No simple analytical form****                      ********Monte Carlo**

- pz() not known work
- in the transverse plane

**W********l****+******

**Z********l****+****l****-**

**p****T****(l)**

**p****T****(l****+****)**

## Extracting the Mass

**Monte Carlo****	**
**pp****W/Z production**
**Detector effects**
**Need to understand the leptonic and hadronic energy scale and resolutions**
**Selection cuts, efficiencies, and acceptances **

## 80.470.09 GeV

- Central Electrons

- 80.480.14 GeV

- 80.430.11 GeV

- pT(e)

- mT

- Forward Electrons

- 80.770.23 GeV

**Preliminary**

- 80.470.09 GeV

**Preliminary**

- mT

**Notes:**
Shown here are resuts from the D0 collaboration using W events  that decay to electrons both in the central and forward calorimeters. The results for central Ws have been published in 1998. The results for forward Ws are very new and represent the first precision measurement that uses electrons detected in forward regions where the backgrounds from dijet events are more important.
The various fits show the results for the W mass as measured from a fit to the electron transverse momentum and W transverse momentum in central and forward regions. 
Major sources of uncertainty are shown in this table and the combined D0 result for the W mass is 80.47+-0.09GeV. 

## 80.430.08 GeV

- 80.470.11 GeV

- 80.470.14 GeV

- 80.430.08 GeV

**Preliminary**

- mT

- mT

##  W Boson Mass

**DØ:  M****W****= 80.474 ******** 0.093 GeV**
**CDF:  M****W****= 80.433 ******** 0.079 GeV**

## W-Boson Mass

- Lots of Systematic errors are dependent on data, for example Z calibrations, and hence scale as data.
- Underlying events/pile up affected by “per-bunch” luminosity so reduced by having 100 bunches(132 nsec spacing)

## CDF All Jets Top Mass

## CDF lepton + jets Top Mass

- Different Data Samples

## D0  l+jets Top Mass Result

**m****t **** = 173.3 ± 5.6(stat.) ± 6.2 (syst.) GeV/c****2**

## D0 Top Quark Mass in l + Jets

## Top Quark Mass

##  Tevatron Combined  Top Mass

**Tevatron Average:**
**M****top****=174.3 ******** 3.2 ******** 4.0 GeV**

**contribution to central value**
**w/ correlations**

**DØ**
**dilepton**
**12 ******

**DØ**
**lepton + jets**
**34 ******

**CDF**
**dilepton**
**10 ******

**CDF**
**all hadronic**
**10 ******

**CDF**
**lepton + jets**
**35******

## Top Quark Mass

**Single experiment, l + jets**

## Implications on the Higgs Sector

**Tevatron Averages**
**M****top**** = 174.3 ******** 5.1 GeV**
**    ****M****W**** = 80.448 ******** 0.062 GeV**

- Significant constraint on the Higgs mass!

## Constraining the Higgs

**?**