# Presentation: 268672

## Status of DØ

- Aurelio Juste (Fermilab)
- Physics Advisory Committee
- March 28-29, 2003

- Detector
- Physics
- Run IIb Upgrade

## Overview

**Overview**

- Detector fully installed
- Integrating forward proton detector
- Making increasing use of tracking triggers
- Silicon track trigger installed this summer
- Operating stably and efficiently
- Event reconstruction < 3 days
- Intense work on reconstruction improvements: tracking efficiency, object identification, etc
- Broad range of physics presentations for spring conferences and beyond
- Run IIb upgrade progressing well. Current forecast remains ahead of baseline dates

## Central Tracking System

**Central Tracking System**

- 4 barrel layers
- axial + stereo detectors

- H, F Disks/wedges

- Active Channels: 91% of 800k
- S/N: > 10 all devices
- Cluster Efficiency: > 97%
- No fiducial loss

- Active Channels: 99% of 77k
- Excellent light yield
- Hit efficiency > 98%*** ***

**Barrels**
**+ disks**

**Barrels**
**only**

- 8 axial layers
- 8 stereo layers

## Tracking Performance

**Tracking Performance**

- Impact parameter
- resolution getting
- close to expectation

## Calorimeter

**Calorimeter**

-   _D__Ø __Run II Highest Mass DiJet Event_  ET : 432, 396 GeV (within | |<0.5)
-   Dijet Mass: 838 GeV
-   x ~ 0.4

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

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

## Muon System

**Muon System**

- Match tracks

- J/  

****** ****~ 750 MeV**

-  Coverage to | |<2.
-  Three layers of triggering  scintillator planes.
-     99.9% active
-  Three layers of precise tracking drift tubes.
-     99.5% active

******~80 MeV**

**Global Tracking System**

**Muon System Only**

## Trigger and DAQ System

**Trigger and DAQ System**

- Runs comfortably up to 4x1031 cm-2s-1 and 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 w/ processor replacements
- L3:  Extensive suite of filters available
- DAQ:
- Working to reduce Front End Busy rate.
- All commodities solution easily meets 1 kHz L2 accept specification.

## Data Taking Efficiency

**Data Taking Efficiency**

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

- Last 7 days:
- ~6.6 pb-1 delivered
- ~5.6 pb-1 recorded
-  **85.3% efficiency**

- Rec = Full detector

## Integrated Luminosity

**Integrated Luminosity**

- Definition of “2003 Winter Conference Data Sample” (~60 pb-1)
- to take advantage of improved reconstruction with a single version.

- 91 pb-1
- currently

## Offline Event Reconstruction and Analysis

**Offline Event Reconstruction and Analysis**

- DØ Reconstruction Farm (240 1.8 GHz dual CPU machines)
- 20M event/week capacity
- operates at 85% efficiency
- events processed within days of collection
- 400M events processed in Run II so far

- 6 remote Monte Carlo Farms
- 0.6M event/week capacity
- Running full GEANT, D0 reconstruction and trigger simulation.
- 15 SAM stations for remote
- analysis

- _Globally Distributed Resources_

## QCD Physics: Dijet Mass Cross-section

**QCD Physics: Dijet Mass Cross-section**

- Probe of:
- QCD
- Proton structure at large x
- New Physics search (resonances, compositeness)
- Increased center-of-mass energy extends the reach:
- 	twice  at MJJ = 1.2 TeV
- Data sample:
- L = 34 pb-1
- 2 leading R = 0.7 cone jets in the central region (| | < 0.5),
- Overall 10% uncertainty on luminosity,
- Jet Energy Scale dominant source of systematic uncertainty,
- Consistent with Run I result.
- Good agreement between data and NLO QCD prediction.

- * Inclusive jet cross-section analysis also ready.

## B-Physics: Exclusive B Decays

**B-Physics: Exclusive B Decays**

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

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

- For now focus on J/+- sample:
- Useful for calibration
- Easy  trigger and provides large number    of B mesons.
- Explicit secondary vertex reconstruction    of J/+kaons:

**B****d******** J/********K****S**

## B-Physics: Average B Lifetime

**B-Physics: Average B Lifetime**

- =1.5610.024(stat) 0.074(syst) ps

- =1.760.24(stat) ps

- B  J/K

- BJ/X

_**Inclusive B Lifetime**_

_**B**__****__** Lifetime**_

- 1.5640.014 ps (PDG)

- 1.6740.018 ps (PDG)

## Electroweak Physics

**Electroweak Physics**

- Data sample: 32 pb-1
- 2 opposite-sign isolated high pT muons (pT>15 GeV, | |<1.8)
- 1585 events selected

- Data sample: 50 pb-1
- 2 EM objects, ET>25 GeV, | |<2.5

- Data and expected background agree well at high mass. No excess observed

_**Z’**__****__**e**__**+**__**e**__**-**__** Search**_

- MZ’ > 620 GeV @ 95% CL

- Z()+X) = 263.86.6(stat) 17.3(syst)26.4(lum) pb

_****__**Z(**__****__**)+X)**_

## (5.6 GeV from 1998 PRD)

**Top-Physics: Run I Top Mass in lepton+jets**

- Likelihood method using most of available information (fit to whole event topology)
- Uses D0 Run I statistics (125 pb-1) and selection in the lepton+jets channel: 91 events
- Additional cuts:
- 4 jets exclusively: 71 events
- Cut on background probability: 22 events
- Large improvement in the statistical uncertainty (equivalent to a factor ~2.4 increase in statistics)
- Expect a substantial improvement in the JES systematic from the use of available W mass constraint.

- mt = 179.9 3.6 (stat) 6.0 (syst) GeV

- (5.6 GeV from 1998 PRD)

## Top-Physics: Run II Top Pair Cross-section

**Top-Physics: Run II Top Pair Cross-section**

| 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 |

- First measurement at s = 1.96 TeV.
- tt(NLO) = 6.7-7.5 pb  (30% higher than at s =1.8 TeV)
- Six analysis channels completed so far
- 	(lepton+jets: topological and soft-muon tagging)
- Dielectron and lifetime tagging analyses being         finalized.

##  -

- pT = 47.9 GeV
- ET= 55.1 GeV
- 6 jets
- HT = 482 GeV
- A = 0.16

*** ************-***

***MTC***

- Double-tagged +jets Candidate Event

- DL=0.53cm
- DL/(DL)=14.9

- DL=0.44cm
- DL/(DL)=32.1

## New Phenomena Searches

**New Phenomena Searches**

- Seven analyses presented at the winter conferences.
- Approaching Run I sensitivity.
- Data samples: ~30-50 pb-1

_**SUSY**_
- GMSB SUSY LSP Search:
- 	2 + MET
- 	mLSP > 66 GeV @ 95% CL
- mSUGRA Chargino/Neutralino
- 	ee+lepton+MET (trilepton mode)
- 	xBR < 3.5 (2.2) pb @ 95% CL

- Standard SUGRA (0 LSP)
- 	2jets + MET
- 	sets model independent      cross-section limit vs MET

- Highest MET event (180 GeV)

- 

## New Phenomena Searches

**New Phenomena Searches**

_**Non-SUSY**_
- 2nd Generation LQ
- 	2 + 2jets
- 	 mLQ > 157 GeV @ 95% CL
- Search for deviations from SM in e+X channel
- 	 sets model independent    cross-section limit vs MET
- Search for large extra-dimensions in ee, channel
- Search for large extra-dimensions in  channel (**New!**)

- Lower limits on S(TeV)

## A new capability for DØ

**New Phenomena Searches: ******** Channel**

- The -lepton often plays a relevant role in models of Beyond the SM physics (trileptons in SUSY, 3rd generation LQs, Higgs decays).
- 	 addition of this channel considerably extends the physics reach
- Need a SM channel for calibration: Z
- Two searches at DØ are seeing
-      evidence for the decay Z:
- Comparison of opposite to like-sign
- 	gives an excess consistent with Z:

- e)(1,2 prong)

- )(1,2 prong)

**********************)********(********1,2 prong)**

- A new capability for DØ

## Run IIb Silicon Detector

**Run IIb Silicon Detector**

- Single sided silicon, barrels only
- Inner (vertexing) layers 0, 1
- Axial only
- mounted on carbon support
- Outer (tracking) layers 2-5
- Axial and stereo (tilted sensors)
- Stave structures
- Prototyping essentially done.

- GEANTmodel

- Prototype of mechanical stave
- being thermally tested at SiDet.

- First Layer 0 prototype carbon
- fiber support structure performs
- to specs under deflection tests
- performed atSiDet.

## Run IIb Silicon Detector: Status

**Run IIb Silicon Detector: Status**

- Electrical tests underway for first outer layer silicon module prototype (both axial and stereo readout)
- Sensor order near end of procurement

## Run IIb Trigger Upgrade

**Run IIb Trigger Upgrade**

- Finished prototyping of three major boards of L1 trigger upgrade (items 1,2 and 4)
- Preparation for tests of full L1Cal prototype chain:
-  	            Digital Filter  Clustering  Cal-Track Match
- 	beginning this summer.
- 	Installed analog splitter in L1Cal rack at the Movable Counting House for tests with real signals.
- Progress in firmware design for L1CTT (item 3)

| System | Problems | Solutions |
| --- | --- | --- |
| Cal | 1-Trigger on =0.20.2 TTs  slow turn-on curve
2- Slow signal rise  trigger on wrong crossing |  Clustering
 Digital Filter |
| Track | 3- Rates sensitive to occupancy4- Limited match to calorimeter |  Narrower Track Roads
 Improve Cal-Track Match |
| Muon | No Additional Changes Needed! |  Requires Track Trigger |

## Conclusions

**Conclusions**

- Detector is operating well and the performance keeps improving.
- Already producing lots of interesting physics: QCD, B, EW, Top, New Phenomena.
- Looking forward to new physics results this summer and beyond.
- The D0 upgrade, crucial to take full advantage of the available physics opportunities in Run IIb, is on track.

## Backup Slides

## Forward Proton Detector

**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 out of 18 so far)

## e

******e******

- e

**Higgs Physics**

- Study jet distributions in W/Z(lepton)+jets (first step towards W/Z+H(H bb) search).
- Data sample: 35 pb-1
- MC normalized to data.
- Error band in prediction includes major systematic uncertainty from JES.
- Good agreement between MC (PYTHIA) and data.
- Study l+l- + ET final state.
- Relevant for both Higgs (H  WW*) and non-Higgs related searches.
- Backgrounds: Z/*, WW, tt, W/Z+jets, QCD
- Data samples: 44.5 pb-1 (e+e-), 34 pb-1 (e
- Observed number of events consistent with expectation from background.

## Run IIb Silicon Detector

**Run IIb Silicon Detector**

- Single sided silicon, barrels only
- Inner (vertexing) layers 0, 1
- Axial only
- mounted on carbon support
- Outer (tracking) layers 2-5
- Axial and stereo (tilted sensors)
- Stave structures
- Prototyping essentially done.

- GEANTmodel

- B-tagging performance studied with full GEANT simulation and pattern recognition.
- Algorithm: signed impact parameter
- Loose track selection
- 2 tracks with d0/(d0)>3  or           2 tracks with d0/(d0)>2
-  b ~ 65%/jet

- (based on WH-events, with fiducial b’s)

- Performance meets the physics requirements  (based on the Run II Higgs/SUSY workshop)

## Run II Physics Program: The Larger Picture

**Run II Physics Program: The Larger Picture**

**300 pb****-1**
- Improved mt measurement
- High pT jets constrain proton structure
- B Physics
- Searches beyond Run I sensitivity
**2 fb****-1**** **
- Measure mt (MW) to  ±3 GeV (± 15 MeV)
- Directly exclude mH = 115 GeV
- Significant SUSY and SUSY Higgs searches
- B-physics: constrain the CKM matrix
**5 fb****-1**** **
- 3 Higgs signal @ mH = 115 GeV
- exclude Higgs 115-125, 155-175 GeV
- exclude much of SUSY Higgs parameter space
**15 fb****-1**
- 5 Higgs signal @ mH = 115 GeV
- 3 Higgs signal mH = 115-135, 150-175 GeV
- Ultimate precision for top, EW and B physics
- Ultimate reach for New Phenomena discovery

| Luminosity/Run | IIa | IIb |
| --- | --- | --- |
| Integrated (fb-1) | 2 | 10-15 |
| Instantaneous 
(x1032 cm-2s-1) | 1-2 | 2-4 |

- Replace Silicon Detector by rad-hard version
- Improve b-tagging performance
- Good pattern recognition over || < 2

- Upgrade Trigger
- Mainly L1: increased functionality to contain rates and deadtime
- Incremental upgrades to L2, L3
- and online system