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Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions and Cross Sections Summary and Outlook D Hadronic Branching Fractions and D D Cross Section at ψ 00 (3770) from CLEO–c V. Credé 12 1 Cornell University, Ithaca, NY 2 now at Florida State University Tallahassee, FL Hadron 05 V. Credé Absolute D Hadronic Branching Fractions

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Page 1: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

D Hadronic Branching Fractions andDD Cross Section at ψ′′(3770) from CLEO–c

V. Credé 1 2

1Cornell University, Ithaca, NY

2now at Florida State UniversityTallahassee, FL

Hadron 05

V. Credé Absolute D Hadronic Branching Fractions

Page 2: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 3: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

CESR-cCLEO-c Detector

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 4: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

CESR-cCLEO-c Detector

e+e− → ψ′′(3770) at Cornell

Ü

CESR–c at CornellE beam = (1.5− 5.6) GeV

⇒ √s = (3.0− 11.2) GeV

CESR–c collides e+ e− in order toproduce the ψ

′′(3770)

V. Credé Absolute D Hadronic Branching Fractions

Page 5: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

CESR-cCLEO-c Detector

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 6: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

CESR-cCLEO-c Detector

Solenoid Coil Barrel Calorimeter

Drift Chamber

Inner Drift Chamber /Beampipe

EndcapCalorimeter

IronPolepiece

Barrel MuonChambers

MagnetIron

Rare EarthQuadrupole

SC Quadrupoles

SC QuadrupolePylon

2230104-002

CLEO-c

Ring Imaging CherenkovDetector

Excellent Calorimeter

Excellent Tracking

RICH and dE/dx for PID

Muon Chambers+ A Great Accelerator Team

V. Credé Absolute D Hadronic Branching Fractions

Page 7: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 8: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Hadronic D Decays

Measurements of hadronic charm meson branching fractions playcentral role in study of weak interaction

Serve to normalize many D and B meson branching fractions(normalizing modes: D0 → K−π+ and D+ → K−π+π+)Used to determine Cabibbo–Kobayashi–Maskawa (CKM) matrixelements (e.g. |Vcb | from B→ D∗ l ν requires D meson BF)

CLEO–c will provide most precise measurements of D hadronicbranching fractions

Also, determination of DD production cross sectionsFirst step towards improved constraints on D mixing parameters

First results: 55.8 pb−1 (0.36 M DD pairs)CLEO Collaboration (Q. He et al.), hep–ex/0504003, accepted by PRL

V. Credé Absolute D Hadronic Branching Fractions

Page 9: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 10: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

D Tagging and the Mark III Method

Basic strategy(for most CLEO–c analyses)

Full reconstruction of oneD meson (the tag)Search for 2nd D meson inthe remainder of the event

Identification of D meson candidatesusing beam–constrained mass:

∆E = ED − E beam

M bc =√

E2beam − |pD|2

Reconstruction

Charged tracks: Track fit quality andoriginate from interaction point

π / K separation by dE/dx and RICH

KS → π+π− and π0 reconstruction

3σ cut on ∆E ≡ ED − E0

V. Credé Absolute D Hadronic Branching Fractions

Page 11: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Single Tags and Double Tags

Measurement of single tags and double tags

Ü Ü

⇓ Wanted

Ni = NDD Bi εi

Nij = NDD BiBj εijÜÜ

Measured

Known

Bi =Nij εjNj εij

NDD =Ni Nj εijNij εi εj

Determination of Branching FractionsDetermine yields Ni and Nij

Simultaneously fit forND+D− , ND0D0 , and all Bi

V. Credé Absolute D Hadronic Branching Fractions

Page 12: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Outline

1 IntroductionCESR-cCLEO-c Detector

2 Absolute D-Hadronic Branching FractionsWhy are Hadronic D Decays interesting ?D TaggingFitting the Branching Fractions

3 Results: Branching Fractions and Cross Sections

4 Summary and Outlook

V. Credé Absolute D Hadronic Branching Fractions

Page 13: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Fitting Technique (I)

Simultaneous fit for all BR & cross sections is performed⇒ All correlations and errors properly taken into account

Charged and neutral modesfit simultaneouslyD and D yields measuredseparately

D0 → K−π+ D0 → K+π−

D0 → K−π+π0 D0 → K+π−π0

D0 → K−π+π+π− D0 → K+π−π−π+

D+ → K−π+π+ D− → K+π−π−

D+ → K−π+π+π0 D− → K+π−π−π0

D+ → KSπ+ D− → KSπ

D+ → KSπ+π0 D− → KSπ

−π0

D+ → KSπ+π+π− D− → KSπ

−π−π+

D+ → K−K+π+ D− → K+K−π−

W.M. SunarXiv:physics/0503050accepted by NIM A

V. Credé Absolute D Hadronic Branching Fractions

Page 14: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Fitting Technique (II)

Background sources:D modes not in the fite+e− → continuumMost Cabibbo-suppressed modes small

Errors on signals and background:Tracking, π0, KS systematics(correlates all elements)Resonant substructureCorrelations between D0 and D+

Analysis technique validated by studying simulated DD events

V. Credé Absolute D Hadronic Branching Fractions

Page 15: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Single–Tag Event Yields

3970305-001

104

103

102

10

104

103

102

104

103

102

1.84 1.86 1.88 1.84 1.86 1.88 1.84 1.86 1.88M (GeV/c2)

Eve

nts

/ (0.

002

GeV

/c2 )

+D0 K + ++D K

+ +D K0S

+D0 K 0 ++ +D K 0 + +D K0S

0

++D K 0 ++ +D K0S

+ + +D K K

Yields vary between 0.6 kand ≈10 k events

Signal shape:ψ(3770) lineshape + ISR+ beam–energy smearing,+ reconstruction resolutionBackground shape:ARGUS function

Note: log scale for single tags !

V. Credé Absolute D Hadronic Branching Fractions

Page 16: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Double–Tag Event Yields

3970305-002800

600

400

200

0

600

400

200

0 1.84 1.86 1.881.84 1.86 1.88M (GeV/c2)

Eve

nts

/ (0.

0012

GeV

/c2 )

D+DD0D0 Mass of D for allmodes combinedDT Yields

2484± 51 for D0

1650± 42 for D+

Double–tag modes clean⇒ Statistical yield uncertainties close to

√N ij

V. Credé Absolute D Hadronic Branching Fractions

Page 17: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Example: Tracking Systematics

250

200

150

100

50

00.1 0 0.1 0.2 0.3 0.4 0.5

MM2 (GeV/c2)2

Eve

nts

/ 0.0

1 (G

eV/c

2 )2

0140704-014

( a ) Data: K Detected

2000

1600

1200

800

400

00.1 0 0.1 0.2 0.3 0.4 0.5

MM2 (GeV/c2)2

Eve

nts

/ 0.0

1 (G

eV/c

2 )2 ( b ) MC: K Detected

0140704-015

( c ) Data: K Not Detected

0140704-016

807060

5040

30

20

1000.1 0 0.1 0.2 0.3 0.4 0.5

MM2 (GeV/c2)2E

vent

s / 0

.01

(GeV

/c2 )

2

600

500

400

300

200

100

0

( d ) MC: K Not Detected

0140704-017

0.1 0 0.1 0.2 0.3 0.4 0.5

Eve

nts

/ 0.0

1 (G

eV/c

2 )2

MM2 (GeV/c2)2

ProcedureExample:Reaction D0 → K−π+

Leaving out K⇒ MM peaks

at mass ofomitted K

Efficiency:Ratio of(a) and (c)

Comparisonbetween Dataand MC

V. Credé Absolute D Hadronic Branching Fractions

Page 18: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Systematics

Tracking Systematicsψ(2S)→ J/ψ π+π−

also:ψ(2S)→ J/ψ π0π0

KS from D→ KS ππ(double–tag events)

Source Value (%)Tracking / KS /π0 0.7 / 3.0 / 2.0Particle ID 0.3/π± 1.3/K±

∆E 1.0 – 2.5ΓΨ(3770) 0.6Final State Radiation 0.5 ST / 1.0 DTResonant Substructure 0.4 / 1.5DCSD Interference 0.8Fit Functions 0.5Online/Offline Filtering 0.4MultiplicityDetector Noise

0.2 – 1.3

V. Credé Absolute D Hadronic Branching Fractions

Page 19: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Comparison with PDG

0.4 0.6 0.8 1.0 1.2 1.4 1.6

PDGCLEO-c

0.4 0.6 0.8 1.0 1.2 1.4 1.6

PDGCLEO-c

CLEO−cPDG

CLEO−cPDG

CLEO efficiencies include Final State Radiation (FSR)In some channels, systematics is already the limiting factor

V. Credé Absolute D Hadronic Branching Fractions

Page 20: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Why are Hadronic D Decays interesting?D TaggingFitting the Branching Fractions

Comparison with other direct measurements in PDG

0.010 0.020 0.030 0.040 0.050 0.060

PDG

0.045 0.065 0.085 0.105

PDG

B(D0 → K−π+) B(D+ → K−π+π+)

PDG band corresponds to the average of all direct measurements⇒ Not a global fit !

V. Credé Absolute D Hadronic Branching Fractions

Page 21: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Cross Sections and Absolute Branching Fractions

Determination of cross sections(scaling N DD by the luminosity)

σ (e+e− → DD) = (6.23± 0.09± 0.21) nb

σ (e+e− → D0D0) = (3.51± 0.07± 0.14) nb

σ (e+e− → D+D−) = (2.72± 0.07± 0.09) nb

Comparison with BES(PLB 603, 130 (2004))

(6.14 ± 0.12 ± 0.50) nb

(3.58 ± 0.09 ± 0.31) nb

(2.56 ± 0.08 ± 0.26) nb

⇒ much larger

Ü

Values higher thanthose of MARK III

Currently, most precise dataDetermination of charged to neutral ratio(→ next slide)

V. Credé Absolute D Hadronic Branching Fractions

Page 22: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Charged to Neutral Ratio

0.9

1.0

1.1

1.2

0.5

0.6

0.7

0.8

10.572 10.580 10.588 3750 3760 3770 3780 3790E [ GeV ] E [ MeV ]

This analysis

Predictions: M. Voloshin(hep-ph/0402170)

Ü

Rchargedneutral = σ(e+e−→D+D−)

σ(e+e−→D0D0)= 0.78± 0.02± 0.02

Discrepancies ⇒ Speculation of 4–quark component of ψ(3770)(M.V., hep-ph/0504197)

DB

V. Credé Absolute D Hadronic Branching Fractions

Page 23: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

CLEO–c Absolute Hadronic BF: Summary

First results based on (arXiv:hep–ex/0504003)

55.8 pb−1 of e+e− colllisions9 decay modes⇒ Including reference branching fractionsB(D0 → K− π+) = (3.91± 0.08± 0.09) %B(D+ → K− π+π+) = (9.5± 0.2± 0.3) %

Comparison with PDG: Branching fractions a little bit higher⇒ CLEO measurements corrected for FSRAlready systematics limited in some modes⇒ New data will reduce statistical errors even moreCross sections:σ(ψ

′′ → DD), σ(ψ′′ → D0D0), σ(ψ

′′ → D+D−), and Rchargedneutral

V. Credé Absolute D Hadronic Branching Fractions

Page 24: Absolute D Hadronic Branching Fractionshadron.physics.fsu.edu/~crede/FILES/ddbar.pdf · 2007. 7. 27. · Introduction Absolute D-Hadronic Branching Fractions Results: Branching Fractions

IntroductionAbsolute D-Hadronic Branching Fractions

Results: Branching Fractions and Cross SectionsSummary and Outlook

Hadronic D Decays: Outlook

There will be more data available for this analysis281 pb−1 as of this summerStatistical error will be reduced by a factor of 2

Addition of Cabibbo–suppressed hadronic D decays⇒ including π0

D mixing constraints(hep–ph/0507238, submitted to PRD)

V. Credé Absolute D Hadronic Branching Fractions