# Presentation: 722859

## DZERO Status and Prospects

**Jerry Blazey**

- URA Visiting Committee March 14-15, 2003

## Overview

**Detector fully installed**
**Now integrating forward proton detector**
**Making increasing use of tracking triggers**
**Silicon track trigger installed this summer**
**Operating stably and efficiently **
**Event reconstruction <3 days**
**Broad physics presentations for spring conferences and beyond**

- URA Visiting Committee March 14-15, 2003

## Slide 3

- URA Visiting Committee March 14-15, 2003

## Silicon Microstrip Tracker

_**Silicon Microstrip Tracker**_

**4 barrel layers**
**axial + stereo strips**

**H, F Disks/wedges**

**S/Noise: > 10 all devices **
**Active Channels: 91% of 1M**
**Cluster Efficiency: > 97%**
**No fiducial loss**

- p-side pulse-height (ADC)

**p-side pulse height**
**1 mip ~ 25 counts**
**Signal/Noise ~ 12**

**MIP, Noise at 2**** **

**Barrels**
**+ disks**

**Barrels**
**only**

- URA Visiting Committee March 14-15, 2003

## Scintillating Fiber Tracker

**Active Channels: 99% of 80k**
**Light yield excellent**
**Hit efficiency > 98%*** *

- track 

- Light yield

**8 axial layers**
**8 stereo layers**

- URA Visiting Committee March 14-15, 2003

## Tracking Performance

_**Tracking Performance**_

- track

- x

- y

**Impact **
**Parameter**
**Resolution**

- Impact
- parameter

**Mean = 0.9 ******** 2.2 ********m**
**Sigma = 36.3 ******** 1.8 ********m**
**Beam ~ 30 ********m ******** IP resolution ~ 20 ********m**

**X-Y vertex location of ********  to e****+**** e****-**

- URA Visiting Committee March 14-15, 2003

## Resonances

_**Resonances**_

- K     

-      p

-      K

- 

- 

- 

- 

- 

- URA Visiting Committee March 14-15, 2003

## Muon System

- Connect tracks

**J****/******** ******** ********+********-**

- scintillator

**Muon System standalone**
****** ****= 750 MeV**

**Match to  CFT tracks**
**70 MeV**

**  ****Three layers of triggering  scintillator planes.**
**  ****Three layers of precise tracking drift tubes****.**

- shielding

**Active Scintillator Channels: 99.9%**
**Active Tracking Channels 99.5%**

- URA Visiting Committee March 14-15, 2003

## Calorimeter

_**Calorimeter**_

_**Run II Highest Mass DiJet Event**_**E****T**** ****: 432, 396 GeV**
**Dijet Mass: 838 GeV**
**X ~ 0.5**

**Liquid argon calorimeter****with uranium absorber**

**Active Channels:**
**99.9% of 50K**
**Working well at low and high energies**** **

- URA Visiting Committee March 14-15, 2003

## A new capability for DØ:   Z  +-

- Data:Opp sign  49 evts
- Like sign  35 evtsDiff         14 ± 9
- Signal: 50pb-1 MC          13 ± 4

**First ******** leptonic electron decay**
**Second ******** decay hadronic one prong decay**
**Comparison of  opposite to like sign ******** excess**

- DØ Run II Preliminary

- URA Visiting Committee March 14-15, 2003

## Forward Proton Detector

****

** ****t**

- Elastic scattering data

- Scintillating fiber detector inside

**Routinely and reliably insert pots in every store**
** ****Detectors perform as designed (good efficiency, resolution) **
** ****Have observed diffractive and elastic events **
** ****Heretofore standalone, integrating into trigger/daq**
** ****10 (of 18) pots now being integrated into DAQ.**

- URA Visiting Committee March 14-15, 2003

## Trigger/DAQ

**Runs comfortably up to 4E31 cm****-2****s****-1**** & will keep pace with luminosity growth as tracking triggers completed, CPUs added. **
**L1 >100 independent trigger bits**
**Operating with Cal & Muon**
**CTT & PS integration underway**
**L2 **
**Operating with CAL, Muon, Global**
**CTT, STT integration underway**
**Input rate expansion spring w/ processor replacements **
**L3 Extensive suite of filters available**
**DAQ**
**Working to reduce Front End Busies.**
**All commodities solution easily meets 1 kHz L2 accept specification.**

- URA Visiting Committee March 14-15, 2003

## Luminosity and Efficiency

**Factors Determining Inefficiency:**
**~5% front-end busy**
**~5% are losses due to store &   run transitions**
**~5% “incidentals”**

- URA Visiting Committee March 14-15, 2003

## Latest Performance

**Expectations:**
**Typical Run Efficiency:  90%**
**Typical Week Efficiency:  85%**

**Feb 17-23, 2003**

- URA Visiting Committee March 14-15, 2003

## Farm Production

**DØ Reconstruction Farm—20M event/week capacity- operates at 85% efficiency—events processed within days of collection.  400M events processed in Run II. **
**DØ Monte Carlo Farms—0.6M event/week capacity-globally distributed resources. Running Full Geant and Reconstruction and trigger simulation**

**FNAL farm CPU utilization for the past year**

**March 02**

**Feb 03**

**Commissioning**
**New nodes**

**Full farm in production in Nov, 02**

**# Processors**

- URA Visiting Committee March 14-15, 2003

**Notes:**
The farm utilization plot is extremely impressive, but this plot doesn’t show that since the new processors were so much faster, that the capacity of the farm actually went up by something like factor of 4.  The turn on can be seen to be smooth, and the only reason at there is a slope between oct and nov is because the nodes were released to us in stages.  The slight downward slope in Jan etc was caused by some database lockouts due to “killer queries” from users (that’s the working hypothesis, but not proven) and some resource starvation caused by competition for the drives.  You can see our monthly downtimes, and the fact we skipped one and the other major down dip were caused by a tape that got stuck in drive on a weekend and brought the system to its knees. The rest are problems with the SAM station and the one at the end is when Mike was serving on the Top EB. The fact that I can recount each major problem is an indication of the stability of the system.

I don’t know how many MC events have been generated in total, some low 10s of millions
The 400 Million includes the fact that many events are processed more than once.  Reco crashes irrecoverably about 0.5% of the time, it takes about 20 GHz sec/event.   With reco crashes, merge failures and delivery failures, the ratio of reco TMBs available to users/raw events collected is about 97-98%.  We are working on pinning that number down with the goal of improving it.

## Representative Physics Analyses

**QCD: Dijet Mass**
**B: Exclusive States, Lifetimes**
**EW: Z to ********, Z’ to ee**
**Top: Cross Section, Run I mass**
**Higgs Studies**
**New Phenomena Searches**

**Just a note on upcoming talks: LaThuile: 5 , Moriond EW: 3, Moriond QCD: 1 + 4 shared, DPF: 15, APS: 35**

- URA Visiting Committee March 14-15, 2003

## QCD: Dijet Mass Cross Section

**Probe of**
**QCD**
**hunting for resonances**
**proton structure at large *****x***
**quark compositeness**
**Data sample:*****	******	******	******	******	***
**34 pb****-1**
**-   ********R = 0.7 cone jets**
**|********jet****| < 0.5**

**twice the ******** at 1.96 TeV**

- URA Visiting Committee March 14-15, 2003

## Dijet mass spectrum

- URA Visiting Committee March 14-15, 2003

## Exclusive B Decays and Lifetimes

_**Exclusive B Decays and Lifetimes**_

- L= 40 pb-1

**J/******** **********************

**Combine J/******** with track or **
**combine J/******** with K* and**
**then require decay length **
**significance>3.0**

**B****+****** **J/********K****+**

**B****d******** J/********K****’o**

- URA Visiting Committee March 14-15, 2003

## Inclusive B lifetime

_**Inclusive B lifetime**_

- ps

- ps

- (PDG)

- b     J/ X

- 

- URA Visiting Committee March 14-15, 2003

## Charged B & Lifetime

- B+-    J/Psi K+-

- <>=1.76   0.24 ps (stat)

- <>=1.674   0.018 ps (PDG)

- URA Visiting Committee March 14-15, 2003

## 

**Selection**
**|************| < 1.8**
**pair of oppositely charged muons**
**P****T**** > 15 GeV**
**                ****>  2.0**
**Isolation**
**timing cut removes cosmics**
**1585 events pass cuts**

_**Electroweak: Z     **__****_** **

******Br = 263.8 ****±**** 6.6 (stat) ****±**** 17.3 (sys) ****±**** 26.4 (lum) pb**

- URA Visiting Committee March 14-15, 2003

## This measurement

- URA Visiting Committee March 14-15, 2003

## Z'     ee Search

_**Z'     ee Search**_

**Expected in left-right symmetric models**
**Data sample**
**50 pb****-1**
**single electron **
**|********| < 2.5**
**E****T**** > 25 GeV**

**MZ' > 620 GeV @ 95% c.l.**

**Data and expected background**
**agree well at high mass,**
**no excess observed**

- URA Visiting Committee March 14-15, 2003

## Run I Top Mass Measurement in the Lepton+Jets Channels

**Likelihood method using most available information**
**Uses D****Ø ****Run I statistics (125 pb****-1****) & selection ******** 91 events**
**Additional cuts for this analysis****:**
**	****4 Jets exclusively:   71 events **
**	****P****b****:  22 events (pure sample****)**

*(5.6 GeV from 1998 PRD)*

**Improvement equivalent to a 2.4 increase in statistics**

**Details to be presented at an upcoming Wine and Cheese seminar**

- URA Visiting Committee March 14-15, 2003

## Top

**First cross section measurement at 1.96 TeV **
**Cross section predictions between 6.7 – 7.5 pb (30% higher than Run I)**
**Six analysis channels (tt********W****-****W****+****bb)**

- Lepton+jets
- (topological)

- e+jets, +jets

- Br = 14.7%

- Lepton+jets
- (soft muon tag)

- Dileptons

- e+jets/, +jets/

- e and  

- Br = 14.7%

- Br = 2.5 and 1.2%

- URA Visiting Committee March 14-15, 2003

## Results

_**Results**_

| Channel | Lum(pb-1) | Expected 
Background | Expected Signal | Obs. |
| --- | --- | --- | --- | --- |
| e+jet | 50 | 2.7+/-0.6 | 1.8 | 4 |
| +jet | 40 | 2.7+/-1.1 | 2.4 | 4 |
| e+jet/ | 50 | 0.2+/-0.1 | 0.5 | 2 |
| +jet/ | 40 | 0.6+/-0.3 | 0.4 | 0 |
|  | 43 | 0.60+/-0.30 | 0.30+/0.04 | 2 |
| e | 33 | 0.07+/-0.01 | 0.50+/0.01 | 1 |

**Jets: 0.5 cone Improved Legacy Algorithm with JES corrections**
**Electrons: Central only, Selected based on simple cone, shower shape, EM fraction, Match with track (******** and E/p)**
**Muons: Tracks in muon system, Tracks in central tracker**
**Missing Et: From calorimeter with JES corrections and muon correction**

- URA Visiting Committee March 14-15, 2003

## Double tagged +jets Candidate Event

*** ************-***

***MTC***

*** ******Jet 1***

***IP***

***SV***

***IP***

***SV***

*** ******Jet 1***

**Double tagged ********+jets ****Candidate Event**

*** ******Jet 2***

- URA Visiting Committee March 14-15, 2003

## Higgs Activities

**In collaboration with CDF, undertaken a joint Higgs Sensitivity Study. **
**CDF will study HW, D0 HZ channels.**
**Preliminary discussions by June.**
**Concentrating on study of the background from W/Z(********lepton) + jets production**
**First step towards W/Z (********leptons) +H (********bb) measurement**
**The W/Z + b-jets distributions related to W/Z+ jets distributions**
**H********WW********* (******** ee********e********) decays (observed number of events consistent with expected number of background)**

- URA Visiting Committee March 14-15, 2003

## Some Data/Background Comparisons

**Selection 35pb****-1**
**Pythia/Data Good Agreement**

**Di-jet Mass**

**W****(e********)+jets**

**Dot : Data**
**Bar : MC**

- QCD

**Combined Z(ee)+jets and**** ****Z(********)+jets**

**Di-jet Mass**

- URA Visiting Committee March 14-15, 2003

## New, New Phenomena Results

_**New, New Phenomena Results**_

**mSUGRA Chargino/Neutralino Search**
**Tri-lepton mode **
**excludes ****xBR = 3.5-2.2 pb**
**GMSB SUSY LSP Search**
**2******** + mE****T**
**95% CLimit m (LSP) = 66 GeV **
**close to Run I**
**SUGRA neutralino LSP Search**
**Jets + mE****T**
**Sets model-ind cross                       section limit as a function                    of mE****T,**

- URA Visiting Committee March 14-15, 2003

## 
Limits on New Physics in an e- Search
Sets limit on cross section as a function of mET
Search for 2nd Gen LQ
2  + 2 jets
MLQ > 157 GeV 

**Limits on New Physics in an e-******** Search**
**Sets limit on cross section as a function of mE****T**
**Search for 2nd Gen LQ**
**2 ******** + 2 jets**
**MLQ > 157 GeV **

- URA Visiting Committee March 14-15, 2003

## Large Extra Dimensions Search 

_**Large Extra Dimensions Search **_

**Model framework: string theory w/ SM restricted to D3-brane, gravity propagating in extra dim’s. Virtual graviton diagrams contributing to dilepton and diboson production. **
**50pb****-1**** ee and ******** channels and 30pb****-1**** ******** channel**
**Combined dodel dependent 95% CL lower***** *****limit on Planck scale M****S **** in TeV**** **

- URA Visiting Committee March 14-15, 2003

## Signal/Theory

- Fit to 2-D distributions to extract SM, interference, and direct gravity terms; use topologies w/ at least 1 EM obj in central calorimeter

-  a New Channel!

- ee Channel

- URA Visiting Committee March 14-15, 2003

## 
Detector operating well.
Producing lots of interesting physics
QCD, B, W&Z, Top,
Limits approaching Run I sensitivity
Looking forward to new physics this summer and beyond...

**Detector operating well.**
**Producing lots of interesting physics**
**QCD, B, W&Z, Top,**
**Limits approaching Run I sensitivity**
**Looking forward to new physics this summer and beyond...**

- URA Visiting Committee March 14-15, 2003

## Silicon Status

**Radiation **
**Increase of bias                                             current measured                                  and consistent                                     with expectations**
**Infers depletion                               voltage exceeds specifications above 3.6 fb****-1**
**100% loss inner layer by 4.9fb****-1**
**50% Uncertainty**
**Active Ladders/Wedges**
_**Device**_**	****	**_**Oct 01**_**	****	**_**Feb03**_**	****	**_**Mar 03**_
**Ladders: ****	****93.4%****	****	****93.1%****	****	****88.4% **
**F-wedges: ****	****92.7****	****	****91.5****	****	****91.3**
**H-wedges:****	****86.0****	****	****86.0****	****	****85.4**

- URA Visiting Committee March 14-15, 2003

## L1CTT

_**L1CTT**_

**Providing tracks to L1muon**
**L1 terms (in triggers now)**
**Commissioning L2 and track and preshower cluster lists**

- L1 terms               Occupancy

- URA Visiting Committee March 14-15, 2003

## STT

- Silicon Trigger Card (STC)

**30****o**** azimuthal units, 6 crates**
**Common Motherboard w/ PCI communication**
**Huge progress last calendear year, from prototypes to complete production **
**Commissioning 1****st**** sector at DØ **
**Firmware debugging**
**Interface with DØ systems**
**Operational Spring 2003**

- URA Visiting Committee March 14-15, 2003

## Forward Preshower Detector

- u,v Stereo Layers with  2*X**0*  Lead Absorber
- 14,988 channels: 99% active.

_**Forward Preshower Detector**_

***L0, FPS, ICD on EC-head***

- System instrumented June 2002
- Offline reconstruction using matched u, v  clusters and energy correlation  requirement

- URA Visiting Committee March 14-15, 2003