# Presentation: 544010

## DZERO Report

**Detector**
**Physics**
**Run IIb**
**Jerry Blazey**
**Northern Illinois University**

- 11/15/2002

## Briefly

**Detector:**
**All detectors in place, commissioning forward preshower (FPS) and proton detector (FPD).**
**Change to ethernet-based DAQ very successful**
**L1 Central Track Trigger (CTT) in commissioning, now communicating with L1 Muon, DAQ.**
**Silicon Track Trigger (STT) under construction.**
**Operations:**
**Set a series of operation, processing, analyses goals for fall/winter – highly successful!**
**Recording physics data with good efficiency.**
**Reconstruction farms in place for high luminosity.**
**Intense work on reconstruction improvements: tracking efficiency, object identification, etc****.**
**Physics analyses underway for spring conferences**

- 11/15/2002

## Silicon Microstrip Tracker Status

_**Silicon Microstrip Tracker Status**_

- Track finding in barrels and disks

- Barrels
- + disks

- Barrels
- only

- Run II data

-  

- 4 barrel layers
- axial + stereo strips

**p-side pulse height**
**1 mip ~ 25 counts**
**Signal/Noise ~ 12**
**Layer efficiency ~ 97%**

- H, F Disks/wedges

- 11/15/2002

## Silicon Status

**Radiation **
**Increase of bias                                             current measured                                  and consistent                                     with expectations**
**Infers depletion                               voltage exceeds specifications @ 4fb****-1**
**Active Ladders/Wedges**
_**Device**_**	****	**_**Oct 01**_**	****	**_**Feb**_**	****	**_**Now**_
**Ladders: ****	****93.4%****	****	****93.1%****	****	****88.4% **
**F-wedges: ****	****92.7****	****	****91.5****	****	****91.3**
**H-wedges:****	****86.0****	****	****86.0****	****	****85.4**
**No loss in fiducial volume.**
**Some recovery expected during Jan access****.**

- 11/15/2002

## Scintillating Fiber Tracker

**8 axial, 8 stereo layers fully instrumented**
**VLPC readout**
**Performing well**** **
**good light yield**
**layer ******** > 98%*** *

- Occupancy matches expectations

- track 

- Light yield

- 11/15/2002

## Tracking Performance

_**Tracking Performance**_

**Survey-only alignment constants**

- Significant improvement expected from alignment with data in near future

- width = 36 m
- (beam) = 30 m
-   = 20 m

- track

- x

- y

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

- Impact
- parameter

**K****S ******** ********+ ********–**

- 11/15/2002

## Calorimeter

_**Calorimeter**_

- _Run II High E__T__ 3-jet event_ET : 110, 240, 310 GeV
- Etmiss : 8 GeV

- Liquid argon calorimeterwith uranium absorber

- Calorimeter Level 1 triggers for electrons and jets: rates agree with Monte Carlo

- 11/15/2002

## Muon System

- J/  +-

- scintillator

- Muon System standalone
-  = 750 MeV

- Match to  CFT tracks
-  = 83 MeV

**  ****Three layers of scintillator planes for triggering**
**  ****Three layers of drift tubes for precise track measurement**

- shielding

- 11/15/2002

## Forward Preshower Detector

- Extruded triangular scintillator strips with embedded WLS fibers:  14,988 channels
- u,v Stereo Layers with  2*X**0*  Lead Absorber
- Signal: Detector  clear fiber waveguides  VLPCs and Analog-Front End (AFE) Readout

- _Forward Preshower Detector_

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

**  ****System instrumented June 2002**
**  ****Offline reconstruction using matched u, v  **
**    ****clusters and energy correlation requirement**
**  ****Performance being optimized jointly with **
**    ****entire DØ VLPC detectors (CFT, CPS)**

- 11/15/2002

## Forward Proton Detector

****

** ****t**

- Elastic scattering data

- Scintillating fiber detector inside

-  Heretofore standalone
-  Integrating into trigger/daq

- 11/15/2002

## Trigger/DAQ

**L1**
**Cal & Muon available**
**CTT commissioning underway**
**L2**
**Operating with CAL, Muon, Global**
**CTT & PS, STT commissioning underway**
**Input rate expansion early ’03 w/ alpha replacements **
**DAQ**
**Last summer successfully installed an ethernet/commodities based DAQ.  **
**Meets 1 kHz L2 accept specification.**

- 11/15/2002

## L1CTT

**Discriminator input available**
**Providing tracks to L1muon**
**Commissioning **
**L1 terms**
**L2 and track and preshower cluster lists**

- L1 terms               Occupancy

- 11/15/2002

## Luminosity (Through 11/01/02)

_**Luminosity (Through 11/01/02)**_

- (Commissioning etc.)

- CFT Fully Instrumented

- CFT Axial Instrumented

- 11/15/2002

## Recent Performance

_**Recent Performance**_

**Best Week (Nov 4-11)**
**	****Delivered: 3.8 pb****-1**
**	****Utilized: 3.7 pb****-1**** (97%) **
**	****To Tape: 2.9 pb****-1**** (75%)**
**Best Day (Nov 9)**
**	****Delivered: 1.4 pb****-1**
**	****Utilized: 1.4 pb****-1**** (99%) **
**	****To Tape: 1.1 pb****-1**** (80%)**

- 11/15/2002

## Integrated Luminosity (Since CFT Fully Instrumented)

- _Month_       _Del(pb__-1__)_      _Tape(pb__-1__)_    _Eff(%)_
- June		  1.3		0.5		37
- July		  9.1		5.3               58
- Aug.		 11.1		6.4		58
- Sep.		16.3		9.8		60
- Oct.		21.6	         14.0		65
- 10Nov		  6.2		4.6		74

- Steady Improvement:
-      Downtime 10% to 2%
-      FEB/L2 Busy Decreasing

- Total
- Delivered:  66 pb-1
- To Tape:  41 pb-1

- 11/15/2002

## Capabilities

**Trigger List now has ~100 triggers**
**Runs comfortably up to 4E31 cm****-2****s****-1**
**Will keep pace with luminosity                         growth as                                   **
**L1CTT                                      completed **
**L2 CPUs added**
**L2&L3 filters                               added.**

- 11/15/2002

## Processing

**Fermilab Farm**
**200+ CPUs**
**20M events/day**
**Offsite**
**Monte Carlo**
**Expanding capability.**

- 11/15/2002

## Spring/Summer Physics Goals

**Top group:**
**Measure top production cross section **
**Model the data with a combination of top signal, W+jets and QCD background**
**W/Z group:**
**Measure the W and Z production cross section in e, ******** channels **
**Demonstrate production of Ws decaying to ******** **
**NP group:**
**Determine limits on the production of particles generated by a variety of physics beyond the SM (SUSY, LQ, ED...) **
**Higgs group:**
**Measure the W+jets and Z+jets production cross sections in e, ******** channels. **
**QCD group:**
** ****Measure inclusive jet production cross section**
**Demonstrate diffractive physics  **
**B group:**
**Measure b quark lifetime and the b production cross section **
**Observation of different B meson exclusive decay modes **

- 11/15/2002

## QCD/Jets

**Not yet fully corrected **
**no resolution or trigger effects**
**30-50% systematic error in cross-section**
**Preliminary correction for jet energy scale is derived from p****T**** balance in photon + jet events. EM scale set by Z ******** ee events****:**

- Only statistical errors

- Run II

- Jet triggers

- Only statistical errors

- 11/15/2002

## B Physics

_**B Physics**_

******(B) = 492**** ****± ****37 ********m**** **

**  ****J/******** ******** ********+********-**** , J/******** ******** e****+****e****-**
**  ****Reconstructing mesons,hadrons**
**  ****Cross sections**
**  ****B tagging**
**   ****muons **
**   ****electrons (working on it!)**
**   ****displaced vertices**

**First B mesons:**
**B ******** J/******** K******

****

****

- 11/15/2002

## W and Z bosons

**Z ******** ********+********-**

- ~170 evts

- ~ 1000 signal events
- 72% purity

**W ******** ******

**Z ******** e****+****e****-**

**W ******** e******

- 11/15/2002

## W and Z  Cross sections

-  · B (W  e)  = 2.67  0.06 (stat)  0.33 (sys)  0.27 (lum)  nb
-  · B (Z  ee)  = 266  20 (stat)  20 (sys)  27 (lum)  pb
- Re = 10.0  0.8 (stat)  1.3 (sys)
- W = 2.26  0.18 (stat)  0.29 (sys)  0.04 (theory) GeV

- 11/15/2002

## Preparing for Top “Rediscovery”

**A major goal for early 2003**
**W******** e******** + jets scaling in data**
**Necessary for signal search and understanding background**

****** ****1 event**

**W(******** e********) + jets**

****** ****3 events**

- 11/15/2002

## New Phenomena

**	****First generation leptoquark****Run II mass limit**
**	****M****LQ**** > 113 GeV ****for B(LQ ******** ej) = 1**

**	****Run II limits from********pp ******** ee,********, ******** **
**	****M****S****(GRW) > 0.92 TeV (ee/********)**
**	****M****S****(GRW) > 0.50 TeV (********) **
**	****	****(first limit from a hadron collider ****	****in muon channel)**

**Leptoquarks**

- 11/15/2002

## SUSY searches

**Missing Transverse Energy**

*D**Ø Run 2 Preliminary*

- 

- QCD+DY

******+E****T****miss**

**Ready for this physics!**

**E****T****miss ****in jet events**

- Hardware!

**First Run II SUSY limit**** **
**Gauge mediated SUSY********pp ******** ********+E****t****miss**
**Cross section for ********+E****T****miss**** > 0.9pb**

**Trilepton candidate**

|  | eee | ee |
| --- | --- | --- |
| SM Background | 0.9 +- 0.2 | 0.13 +- 0.08 |
| EM Fakes | 1.0 +- 0.3 | 0.6 +- 0.2 |
| Cosmics | --- | 0.145 +- 0.014 |
| Total | 1.9 +- 0.4 | 0.9 +- 0.2 |
| Data | 2 | 1 |

- 11/15/2002

**Published or submitted 121 papers**
**Showing new Run I and Run II Results**

_**Last Word on Run I?**_

- 11/15/2002

## A new measurement of top mass

**Uses **_**all**_** measured quantities per event and their errors **
**All 12 jet combinations, all neutrino momenta**
**Run I dataset**

- Background event

- Signal events

****

****

****

*For each event, signal and background probabilities are added. The probabilities for individual events are then multiplied together****.***

**P****signal**

**P****background**

**m****t**

**P(m****t****)**

- 11/15/2002

## New Preliminary Top Mass

_**New Preliminary Top Mass**_

**m****t****= 179.9 ******** 3.6 (stat) ******** 6.0 (sys) GeV  ***preliminary*** **
**  ****Improves statistical error from 5.6 GeV [****PRD 58 52001, (1998)****] to 3.6 GeV: **
**    ****equivalent to ****a factor of 2.4 in the number of events****  **
**  ****22 events pass final cuts (from fit: 12 S + 10 B)**

*D**Ø Preliminary*

*D**Ø Preliminary*

- 68%
- C.L.

- 11/15/2002

## Run IIb Upgrade

**The present detector was designed for ~ 2fb****-1**** and 2 ******** 10****32**** cm****-2**** s****-1**
**The Director has set the goal of accumulating ~10-15 fb****-1**** before the end of the decade**
**Exceeds radiation tolerance of existing silicon detector**
**Requires higher luminosities, ~ 5 ******** 10****32**** cm****-2**** s****-1****, trigger upgrades**

- Replace Silicon Detector with a more radiation-hard version
- Improve impact-parameter resolution (b-tagging) through additional layers and smaller beampipe
- Maintain good pattern recognition over |h| < 2

- Upgrade Trigger
- Shift functionality upstream and increase overall Level 1 trigger capability – contain rates, dead time
- - Calorimeter clustering & digital filtering
- - Enhance track trigger to respond to      increased occupancies
- - Calorimeter cluster match with track
- Incremental Upgrades to Level 2, Level 3 Triggers and online system

- September 2002 Lehman Review recommended baselining of Run IIb upgrades.

- 11/15/2002

## Run IIb Silicon Detector

**Single sided silicon, barrels only**
**Detector installed in two halves inside collision hall in ~7 month shutdown**
**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

- 11/15/2002

## Run IIb Silicon Performance

**	****b-tagging performance studied with full GEANT simulation and pattern recognition**

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

- mistag rate 1-2%

- b vs. Ejet

- b vs. jet

- b vs.
- fraction ofdead ladders

- Run II workshop assumptions for tight and loose tags

- 11/15/2002

## Reviews of the Run IIb Projects Since April ’02 PAC

**April ‘02: Director’s Review Run IIb Upgrade Projects, E.Temple**
**June ‘02:  Aspen PAC - Stage I approval recommended**
**Aug 12-15 ‘02:  Director’s Review Co-chairs:  E.Temple, J.Pilcher**
**Silicon sub-project “well developed”, design “clearly mature”**
**All five trigger sub-projects deemed “ready for baselining”**
**Project preparedness, quality & depth of staffing noted**
**Sep 24-26 ‘02:  DOE (Lehman) Review**
**“****DOE should move forward expeditiously with CD-1,2,3a”**
**Nov 4-8 ’02:  DOE External Independent Review**
**Jupiter Corporation, called by DOE Office of Engineering & Construction Management**
**Closeout very positive **
**Nov 13-14 ’02:  Review of Project Management Control Systems**

- 11/15/2002

## Conclusions

**DZERO up and running,**
**Balanced physics program established,**
**Upgrade set to go...**
**Ready for and anticipating increasing luminosity**

- 11/15/2002

## Run II Physics Program

_**Run II Physics Program**_

- 2fb-1
**Measure top mass ±3 GeV**
**Measure W mass ± 15 MeV**
**Directly exclude m****H**** = 115 GeV**
**SUSY Higgs search @ large tan ******
**Constrain the CKM matrix**
- 6.5 fb-1
**3******** Higgs signal @ m****H**** = 115 GeV; **
**exclude Higgs 115-125, 155-175 GeV**
**exclude much of SUSY Higgs ****parameter space**
**possible discovery of supersymmetry in very large fraction of minimal SUSY parameter space**
- 11 fb-1
**3******** Higgs signal m****H**** = 115-125, 155-175 GeV; **
**exclude Higgs over whole range 115-175 GeV**
**possible discovery of supersymmetry in larger fraction of parameter space **
- 15 fb-1
**5******** Higgs signal @ m****H**** = 115 GeV; **
**3******** Higgs signal 115-175 GeV**

- Each factor of  two in luminosity yields a significant increase in reach and lays the foundation for the next steps

- 11/15/2002