# Presentation: 670671

## Recent Run 1 ResultsLast updated on July 5, 2001Boaz Klimaklima@fnal.gov

## Recent QCD Results

**QCD********JETRAD**

*******d******2************ dE******T ******d*************** (fb/GeV)**

**x**

**Q****2 ****(GeV****2****)**

**Extends significantly the kinematic reach **
**of previous studies**

***E******T***** (GeV)**

**Currently being**
**used in new global**
**PDF fits by **
**MRST group**

**Phys. Rev. Lett. 86, 1707 (2001)**

**Consistent with**
**pQCD calculations**
** ****over large dynamic **
**range |********|<3, **
**and indicates **
**preference**
**of CTEQ4HJ, **
**MRSTg******** and **
**CTEQ4M PDFs**

**Good agreement with predictions in shape**
**but not in normalization**

**PRL in Print ****Phys.Rev.Lett.86, **
**2523 (2001);**

**PRL in print**
**Phys. Rev. Lett. 86, 1955 (2001)**

**Well described by pQCD and permits evaluation**
**of the sensitivity of the calculations to ********R****-scale;**
**Preference at ********s****3**** for a single hard scale**

**Recent QCD Results**

## W pt and W/Z pt ratio

**W transverse momentum**

- Test of perturbative and non-perturbative QCD over a large range of pt.

**W/Z differential cross section**

- Method can be used to predict W observables using purely pQCD theoretical prediction and measured properties from Z **                                         **

**Data and theory show good agreement. At low pt, the perturbative calculation clearly breaks down and a combined resummed calculation and non-perturbative parametrization is needed.**

- Theory is Giele/Keller PRD57, 4433

## W mass and W width

**W mass and W width**

**Improved W mass measurement**

- -Include previously unused  events with  electrons close to  the boundaries between calorimeter modules. “Edge  electrons”

**Direct measurement of the W width**

-  Avoids using theoretical inputs.
-  Explores the region above W pole where new physics could appear

**->More W->e********events**
**->More Z->ee events lead to  additionally constraint calibration**

**D0’s error on W mass**
** ****reduced by  8%**

******(W) = 2.231 ****+ 0.145****-0.138 ****(stat) ******** 0.092 (syst) GeV**
**SM prediction: ********(W)=2.0937 ********0.0025 GeV**

**The tail region of M****T****(W) is sensitive to ********(W) and can be used to extract ********(W).**

## Extra Dimensions and Technicolor

**PRL 86 (2001) 1156**

**Extra Dimensions**

- We search for Graviton exchange in the e+e- and  Minv vs. cos* distributions

**Technicolor and Z’ Search**

**Submitted to PRL**

**We observe no evidence for technicolor or Z’ production and set limits of about 200 GeV for ********T**** and ********T****, and 670 GeV for Z’**

**We observe no evidence for Extra Dimensions and set limits on the energy scale of extra dimensions between 1.0 and 1.3 TeV for the number of extra dimensions between 2 and 7**

- We search for technihadron and Z’ production in the e+e- Minv distribution

## A quasi-model-independent new physics search strategy

- Question:  Is it possible to perform a *data*-driven search for new phenomena?

**Sleuth**

- 1) Define final states

- 2) Define variables

- 3) Define regions

- 4) Define "interestingness"

- 	5) Run *hypothetical similar experiments*

- 6) Can Sleuth find something interesting?

- top

- bkg

- 7) Does Sleuth find anything interesting in Run I data?

- (yes!)

- No.**  **A systematic search of many final states reveals no evidence of new high pT physics.

- 8) Apply to Run II

## Quaero – DØ Makes its Data Public!

- Quaero: Latin for “to seek”

- http://quaero.fnal.gov/quaero/

- QUAERO automatically optimizes an analysis for a particular signature provided by the user, using DØ data sets and SM backgrounds. QUAERO was demonstrated in eleven separate searches: SM WW, ZZ, and tt production; resonant hWW,ZZ; W’WZ, and Z’  tt production; associated Higgs production; and pair production of first generation scalar leptoquarks. Search for W’WZ is the first of its kind.

- Wh ejj, w/
- kinematic fit to W

- Bckgr

- Signal

- Bckgr

- Signal

- Region of max sensitivity

- Data

- Data

- LQLQ eejj

- hep-ex/0106039,submitted to PRL