workshop on quarkonium, november 8-10, 2002 at cern heriberto castilla dØ at run iia as the new...

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


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…


Tevatron LuminosityTevatron Luminosity


Calorimeters Tracker

Muon System

Beamline Shielding

Electronics

protons

20 m

antiprotons

The Run II DØ DetectorThe Run II DØ Detector


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


DØ Tracker DØ Tracker

125 cm


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


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


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


Muon SystemMuon System

Muon Trigger Counters

DØ Detector in Collision Hall, January 2001


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


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


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


~30% systematic uncertainty

4.8 pb-1 of data

region not measured in Run I

Run II J/ production cross section


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


++-- in D in DØØ

• pT of tracks > 2 GeV


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


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


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

workshop on quarkonium, november 8-10, 2002 at cern heriberto castilla dØ at run iia as the new...

Documents

cern slide

bphysics searches

outside b

d detector slide

b mixing

run iia

physics goals

h disks slide