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Quarkonium Production at DØDØ

Jundong Huang Indiana University

Quarkonium WorkshopFermiLab

September 20-22, 2003

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OutlineOutline• The Run II DØ Detector• J/, (2s) signals • B J/ +X signals observed by DØ c J/ signal

• Quarkonium production at DØ : goals• Preliminary J/ cross section vs rapidity• Preliminary results of (1S) differential

distributions• Conclusions

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Calorimeters Tracker

Muon System

Beamline Shielding

Electronics

protons

20 m

antiprotons

The Run II DØ DetectorThe Run II DØ Detector

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Muon Detector UpgradeMuon Detector Upgrade

• Muon rapidity coverage to eta of 2.0

• Comparing to RunI, shielding reduces backgrounds by 50-100x

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Delivered and Recorded Delivered and Recorded LuminosityLuminosity

Lepton-Photon 2003

B-physics analyses based on integrated luminosity of 114 pb-1

Summer 03 Data Sample

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Luminosity: 114 pb -1

J/ Signal= 290k eventsMass= 3.072 GeV/c2

Width = 74 MeV/c2

J/, , (2s) Signal Signal

(2s) = 8222 eventsMass= 3.668 GeV/c2

Width = 71 MeV/c2

DZero is reprocessing the data with improved tracking.This will increase the J/ efficiency.

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c c signals signals

Requirements:

• M(dimu)-M(J/) <0.2GeV

• pT()>1 GeV• pT(J/)<10 GeV

Indirect J/ productionfrom higher charmoniumstates

c1 and c2 seperated by~45 MeV

The ratio of c1 and c2 is atest of different

quarkoniumproduction models

Luminosity: 114 pb -1

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conversion verticesconversion vertices

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Inclusive Inclusive B B J/ + X Lifetime Lifetime

• Measure inclusive B lifetime

• Separation of prompt and non-prompt J/ production

• ~18% J/ from B decays

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B B J/ + X Signals (1) (1)

Bd J/ Ks0Bd J/ K* B J/ K

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B B J/ + X Signals (2)(2)

Bs J/ b J/

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Quarkonium Production at DØDØ

We intend to measure:- J/, (2S) and (nS) differential cross

sections in several rapidity ranges - Charmonium prompt and non-prompt

production - Quarkonium direct and indirect

production- J/, (2S) and (nS) polarization

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~30% systematic uncertainty

4.8 pb-1 of data

Region not measured in Run I

Run II J/ production cross section

Summer 2002 Results

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Examples of mass plots pT bins (vertical) : 1-2 GeV; 3-4 GeV; 4-6 GeV;

rapidity bins (horizontal):

0.0<|y|<0.6 (6.2k events)0.6<|y|<1.2 (7.6k events)1.2<|y|<1.8 (5.6k events)

Requirements:• pT

>3.0 GeV; ||<1.8

• 3 layer muon tracks matched to central track with at least two silicon hits

• Muon isolation cuts

Upsilon(nS) signals Upsilon(nS) signals Rapidity

pT

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Upsilon(1S) fitted signal widthUpsilon(1S) fitted signal width

fitted signal width in 0.6<|y|<1.2

(1S)

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Upsilon(1S) differential Upsilon(1S) differential distributiondistribution

Normalized differentialdistribution as afunction of (1S)

pT in three

rapidity bins.

There is littlevariation in the

shape of pT

distributions withrapidity.

(1S)

(1S)

(1S)

DZero Preliminary Results

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Upsilon(1S) differential Upsilon(1S) differential distributionsdistributions

Comparison ofNormalizeddifferential distribution:• DØ Run II |y|

<1.8 • CDF Run I |y|

<0.4 DZero Preliminary(|y|<1.8)

(1S)

(1S)

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ConclusionConclusion

• Summer 2003 B-physics analyses based on integrated luminosity of 114 pb-1

• Over 290k J/ and 20k (1S) events reconstructed• Analyses of J/ and (1S) differential cross

sections in various rapidity ranges are underway

c signals from conversions established• We have started to study the J/, (2s) and (1S)

polarization • All data are being reprocessed with better

tracking