# Presentation: 791230

## Latest results from Run 2 at DØ 

**Last updated – Oct. 19, 2001**
**John Womersley, Boaz Klima**
-  (womersley@fnal.gov,klima@fnal.gov)

## Commissioning timeline

- 36x36  fine tune & stabilize;
-  stable operation

- December & January 2002

- 36x36 stores
- Commission CFT & L1 track trigger

- November

- Install AFE8 boards & other completion

- Oct 8 - Nov 16

- Take data & commission Offline software
- with real data;  Calibration & Alignment

- Run until ~ Oct 8

- Increase L3 rate from 4 Hz to ~100Hz
- Complete L1 Cal
- Start bringing up  L2 trigger partially

-  By August 15

- Continue 36 x 36 running
- With detector as described before.

- ~ July 26

- Action

- Dates

**NOW**

**Done**

**Done**

**In Progress**

**In Progress**

**Done**

**In Progress**

**Done**

## Z  ee candidates

**2 EM objects, E****T**** > 20 GeV,**
**isolation and shower shape cuts**

**(uncalibrated energy scale)**

- Leo Chan, Rochester

**m****Z**

**DØ**

## W e candidates

- W e candidates

**EM cluster**
**with track**

**EM cluster**
**with track**

- Vishnu Zutshi
- Brookhaven

**e**

**E****T**

**m****T****(e,********)  ****L****~0.1pb****-1**

## Just for fun . . .

**DØ W + 2 jet (Higgs!) candidate, October 2001**

**Electron**

**Jet 1**
**E****T****raw**** = 17 GeV***

**Jet 2**
**E****T****raw**** = 13 GeV***

**Jet 1**

**Jet 2**

**Electron**

*** Jet E****T**** corrections will be large**

**E****T**

## Di-muon Z candidate

- Two muons recoiling against a jet
- Dimuon mass = 55 GeV (large error)

- Onne Peters
- NIKHEF

## J/ +- candidates

**Di-muons reconstructed in the forward region**

****

**On **
**peak**

**Off**
**peak**
******bb?**

**DØ**

## Muons in jets

- Muon in jet (b candidate)
- Hits in A,B,C layers

- Onne Peters, NIKHEF

- Back to back
- calorimeter jets

## 	This type of event is used to derive the jet energy calibration

****

**jet**

**jet**

****** ****candidate**

- 	This type of event is used to derive the jet energy calibration

- Jets

**DØ**

**DØ**

## Level 3 calorimeter trigger

**EM clusters, p****T**** > 10 GeV**
**Isolated, EM fraction > 0.9**
**|********| < 1.1 **

**Jets, p****T**** > 15 GeV**
**R = 0.7 cone**
**|********| < 1.1**

- fail (prescaled)

- pass

- fail (prescaled)

- pass

- Volker Buescher
- Mainz

## Silicon Detector

- North

- South

- H1

- H4

- F1

- F11

- F12

- B1

- B4

- B6

## DØ silicon performance

**J/******** signal from silicon tracking**

- DØ silicon performance

**K****0**** signal from silicon tracking**

**First reconstructed tracks**
**April 2001**

**Primary vertex**

**Single **
**Run**

## Fiber tracker readout

**Readout under detector**

**Clear Fiber Waveguides**
**carry the signals to VLPC’s**
**Solid state photon counters**
**Operate at LHe temperature**

**Photoelectron peaks in**
**final electronics in DØ **
**1 pe ~ 7 fC**

## The work of many people...

## Slide 15

## Detector in Collision Hall January 2001

## Detector in Collision Hall January 2001

## DØ data in the news

## pp  WH 

**Two b-jets from**
**Higgs decay**

**Missing E****T**

**Electron Track**

**EM cluster**

**Calorimeter**
**Towers**

**p ******

******p**

******pp ******** WH **
**	****    ********bb**
**             ******** ****e******

**Hits in Silicon Tracker**
**(for b-tagging)**