Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
DDØØ at Run IIa at Run IIa as the new as the new
B-Physics/charmonium playerB-Physics/charmonium player
Heriberto CastillaCinvestav-IPN
Dzero Collaboration
Workshop on QuarkoniumNovember 8-10, 2002 at CERN
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Physics Challenges The Upgraded TevatronPhysics Challenges The Upgraded Tevatron
4.82.32.5Interactions / xing
1323963500Bunch xing (ns)
10517.33.2 Ldt (pb-1/week)
5.2 10328.6 10311.6 1030Typical L (cm-2s-1)
1.961.961.8s (TeV)
140 10336 366 6Bunches in Turn
Run 2bRun 2aRun 1b
Run 1 Run 2a Run 2b 0.1 fb-1 24 fb-1 15 fb-1
Peak Lum. achieved over 3.5 1031 cm2s1
Planned to reach Run 2a design by Spring 2003
Physics goals for Run 2 precision studies of weak bosons, top, QCD, B-physics searches for Higgs, supersymmetry, extra dimensions, other new
phenomena
require electron, muon, and tau identification jets and missing transverse energy flavor tagging through displaced vertices and leptons luminosity, luminosity, luminosity…
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Tevatron LuminosityTevatron Luminosity
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Calorimeters Tracker
Muon System
Beamline Shielding
Electronics
protons
20 m
antiprotons
The Run II DØ DetectorThe Run II DØ Detector
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
DØ in RunIIDØ in RunII
• Center of Mass Energy = 1.96 TeV• Expect 2 fb-1 by end of 2004 (RunIIa),
15 fb-1 by 2008 (RunIIb)
• Goals– B Physics ( B lifetime, B mixing, exclusive decays)– J/ and production properties (polarization vs pT)– Comprehensive study of top quark properties– Precise measurements of mtop, mW
– Search for new phenomena (SUSY, technicolor,…)– Search for the Higgs boson– QCD (proton structure, quark compositeness)
• DØ’s strength is high-pT Physics but we can also do low-pT Physics
• Requires– Measurement of leptons (e, ), jets, missing pT – Flavor tagging of jets
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
DØ Tracker DØ Tracker
125 cm
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Silicon Microstrip Tracker (SMT)Silicon Microstrip Tracker (SMT)
4-layer barrel cross-section
Barrels F- Disks H- Disks
sngl + dbl double single
Stereo 0, 2, 90 +/ -15 +/ -7.5
Channels 387072 258048 147456
Modules 432 144 96
I nner R 2.7 cm 2.6 cm 9.5 cm
Outer R 9.4 cm 10.5 cm 26 cm
6 Barrels
12 F Disks
4 H Disks
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Tracking PerformanceTracking Performance• pT dependent impact
parameter resolution at vertex is 100 m using SMT only tracks and improves to 48 m when CFT data is combined with SMT data--and is expected to improve further as studies progress
Ks +-
track
x
y
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Fully commissioned
Bottom B/C Scintillators
A- ScintPDTs
Forward Tracker (MDTs)
Shielding
Forward Trigger
Scintillators
• Central and Forward regions, coverage up to = ± 2
• Three layers: one inside (A), two outside (B, C) the toroid magnets
• Consists of scintillators and drift tubes
• Central Proportional Drift Tubes (PDT’s)
• 6624 drift cells (10.1 5.5 cm) in 94 three- and four-deck chambers
• Central Scintillation Counters
• 360 “cosmic ray” counters outside the toroid ( = 22.5)
• 630 “A” counters inside ( = 4.5), = 0.1
• Forward Mini Drift Tubes (MDT’s)
• 6080 8-cell tubes in 8 octants per layer on North and South side, cell cross-section 9.4 9.4 mm
• Forward Scintillation Counters (Pixels)
• 4214 counters on the North and South side
• = 4.5 matches the MDT sector size
Muon SystemMuon System
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Muon SystemMuon System
Muon Trigger Counters
DØ Detector in Collision Hall, January 2001
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Muon Timing
Cosmic rays
’s from Collisions
Timing cuts reduce cosmic bckg., could aid in detection of slow moving particles
M = 3.08 0.04 GeV
= 0.78 0.08 GeV
Muon stand alone system
Muon plus central tracking
J/ invariant mass
Matching of central tracks to ’simproves momentum resolution
CHEP02 – 31st International Conference on High Energy Physics, Amsterdam, 24 – 31 July, 2002
Muon System PerformanceMuon System Performance
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
L3/DAQ Tape
2.3 (7.5) MHz
5 kHz 1 kHzL3
Trigger50 Hz
Decision times: ~4.2 s ~100 s ~50 ms
Level 1• Subdetectors• Towers, tracks,
clusters, ET
• Some correlations• Pipelined
Level 2• Correlations• Calibrated Data• Separated vertex• Physics Objects e, ,
j, , ET
Level 3• Simple
Reconstruction• Physics
Algorithms
• Entire Trigger Menu configurable and downloadable at Run start
• Trigger Meisters provide trigger lists for the experiment by collecting trigger requests from all physics groups in the Trigger Board
• All past and present trigger lists are stored and maintained in the dedicated trigger database
DDØ Trigger SystemØ Trigger System
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
DDØØ Beauty/Charmonium Physics Beauty/Charmonium Physics ProgramProgram
J/ψ cross section and polarization Y cross section B Lifetimes
Average B lifetime: b J/X b lifetime: bJ/0
B0s lifetime and width: B0
sJ/
CP violation, sin(2): B0J/ K0s
B0s mixing: BsDs l X, BsDs(n)
Rare decays, cross sections
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
~30% systematic uncertainty
4.8 pb-1 of data
region not measured in Run I
Run II J/ production cross section
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
θ = angle(J/ψlab,μJ/ψ)
I(θ) = 3/2/(α+3) (1+ α cos2 θ)
α = (σT -2σL)/(σT +2σL)
pt(J/ψ) > 10|η(J/ψ)| < 1.8 pt(μ) > 2η(μ)| < 1.9
Future measurements: J/ polarization
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
++-- in D in DØØ
• pT of tracks > 2 GeV
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
Average B Hadron LifetimeAverage B Hadron Lifetime
• 416 ± 30 signal events• 2184 ± 47 prompt J/’s (B) = 492 ± 37 m
(PDG: (B) = 469 m)
Same sample as B± J/K±
pT(J/)>4 GeV/c
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
DDØØ’s First B Hadron Candidates’s First B Hadron Candidates
• ~5 pb-1
• J/ vertex– pT(track)>2 GeV/c,
matched to a muon– Positive decay length
• pT(K)>0.5 GeV/c
• B vertex– pT(B)>10 GeV/c 2<10– Decay length>120
m– Colinearity angle
(pl)>0.9
Workshop on Quarkonium, November 8-10, 2002 at CERN Heriberto Castilla
ConclusionConclusion• First physics results at 1.96 TeV
– J/ studies– J/ cross section (cross checks with Run I measurement)– Average B Lifetime consistent with previous measurements– First observation in D0 of a charged B
• Tools to work on quarkonium – Prompt J/ (’) and from Bs– Upsilon– Polarization measurements radiative decays
• Improvements in store:– CTT and STT triggers soon– Increased rate of J/ and to tape
Top Related