b decays to d s +() and d +

BB Decays to Decays to DDss+(*)+(*) and and DD*+*+

Ben BrauBen BrauMassachusetts Institute of TechnologyMassachusetts Institute of Technology On behalf of the On behalf of the BBAABBAR AR collaborationcollaboration

Meeting of the Division of Particles and Fields of the American Physical Meeting of the Division of Particles and Fields of the American Physical SocietySociety

August, 2000August, 2000

Submitted papers: Submitted papers: BABAR-CONF-00/13BABAR-CONF-00/13BABAR-CONF-00/06BABAR-CONF-00/06

August 2000 Ben Brau DPF 2000

Data Sample:Data Sample:On the On the (4S)(4S) resonance resonance 40 MeV below BB threshold (off resonance)40 MeV below BB threshold (off resonance)

Study of inclusive Study of inclusive DDss(*)(*) production in B decays. production in B decays.

Measurement of Measurement of BB00DDss(*)+(*)+DD*-*- branching fraction branching fraction

with a partial reconstruction technique. with a partial reconstruction technique.

Measurements and data samplesMeasurements and data samples

: 5.2 fb: 5.2 fb-1-1

(~5,900,000 BB)(~5,900,000 BB)

Measurement of the branching fractions for the Measurement of the branching fractions for the decays decays BB00DD*+*+andand BB00DD*+*+

: 7.7 fb: 7.7 fb-1-1

on resonanceon resonance

(~ 8,700,000 BB)(~ 8,700,000 BB)

: 1.2 fb: 1.2 fb-1 -1

off resonanceoff resonance

Ldt

Ldt

Ldt


Physics MotivationPhysics Motivation These measurements can probe These measurements can probe VVub ub and and VVcb cb and test factorizationand test factorization

The The BBAABBARAR detector detector Charged particle tracking: Combined Silicon Vertex Tracker and Drift Charged particle tracking: Combined Silicon Vertex Tracker and Drift

Chamber momentum resolution (Chamber momentum resolution (ppTT/p/pTT)) 2 2 = (0.0015p= (0.0015pTT) ) 22 + (0.005) + (0.005) 22

Particle identification: Particle identification: dE/dxdE/dx in SVT and DCH ; Cherenkov angle in in SVT and DCH ; Cherenkov angle in DIRC: 2.5 DIRC: 2.5 kaon-pion separation to 3.5 GeV kaon-pion separation to 3.5 GeV

Photon detection: CsI(Tl) crystal calorimeterPhoton detection: CsI(Tl) crystal calorimeter Branching fraction measurementsBranching fraction measurements Yields and efficienciesYields and efficiencies Systematic errorsSystematic errors ResultsResults

IntroductionIntroduction


Inclusive reconstruction of Inclusive reconstruction of DDss from from B B decays decays

DDss

DDss

DD

(Cabibbo-suppressed)(Cabibbo-suppressed)

NNDsDs = 18270 ± 200 = 18270 ± 200

mmDsDs= 1968.5 ± 0.1(stat) MeV = 1968.5 ± 0.1(stat) MeV = 5.4 ± 0.1 MeV= 5.4 ± 0.1 MeV

Selection criteria:Selection criteria:–kaon IDkaon ID–|m(|m(KKKK)-m()-m()| < 8.0 MeV)| < 8.0 MeV–|cos|cosHH| > 0.3| > 0.3

Efficiency: 40.5 ± 1.0%Efficiency: 40.5 ± 1.0%

m(m(DDss )-m()-m(DD ) = 98.7 ± 0.2(stat) MeV) = 98.7 ± 0.2(stat) MeV

KK++KK--


DDss momentum spectrum momentum spectrum

BF(BF(BBDDssXX ) = (11.9 ) = (11.9 0.3 0.3 1.1 1.1 3.0 ) 3.0 )

1010-2 -2

(uses PDG value of BR((uses PDG value of BR(DDss )=3.6)=3.60.9%)0.9%)

PDG 2000 (10.0 PDG 2000 (10.0 2.5) 2.5) 1010-2-2

Systematic sourceSystematic source Error (%)Error (%)

NNBBBB 3.63.6

Tracking efficiencyTracking efficiency 7.57.5

Particle identificationParticle identification 0.80.8

DDss yield yield 3.03.0

BR( BR( KK++KK-- )) 1.61.6

TotalTotal 9.09.0

After continuum After continuum subtraction:subtraction:

Peterson fragmentaion Peterson fragmentaion functionfunctionc c = (12.5= (12.50.6)0.6)1010-2-2

Inclusive reconstruction of Inclusive reconstruction of DDss from from B B decays decays


Selection criteriaSelection criteria::

– EE>50 MeV>50 MeV

– Veto Veto from from 00

– 1953<M(1953<M()<1984 Mev)<1984 Mev

Systematics Sources Systematics Sources Error%Error%

N N BBBB 3.63.6

Tracking efficiencyTracking efficiency 7.57.5

Photon efficiencyPhoton efficiency 2.52.5

Particle IdentificationParticle Identification 0.80.8

DDss yield yield 7.77.7

Daughters’ BFDaughters’ BF 3.13.1

TotalTotal 12.012.0

DDs s ** D Dss

BF(BF(BBDDss* * X X ) = (6.8 ) = (6.8 0.7 0.7 0.8 0.8 1.7) 1.7) 10 10-2-2

(uses PDG value of BF((uses PDG value of BF(DDss ) = 3.6 ) = 3.6 0.9% 0.9% ) )

N(N(DDs s **) = 3029 ± 151) = 3029 ± 151

m= 143.4 ± 0.3MeVm= 143.4 ± 0.3MeVmm=7.4 ± 0.4 MeV=7.4 ± 0.4 MeVKK++KK--

Inclusive reconstruction of Inclusive reconstruction of DDss** from from B B decays decays


BB00DDss(*)+(*)+DD*-*- Branching Fractions Branching Fractions

Method:Method:

Fully reconstruct Fully reconstruct DDss(*)+(*)+

Partially reconstruct Partially reconstruct D*D*- - ( ( ))

c

c

s

d

b

d

W

0B

(*)sD

*D

22

2miss pppEEmss DBD

s

DDss(*)+(*)+

--

( ( ))

BB00

D*D*--

ambiguityambiguity

0D

0D


DDss**- - missing mass missing mass DDss

-- missing missing

massmass


Yield: 628 ± 55Yield: 628 ± 55 Yield: 195 ± 29Yield: 195 ± 29


Feed through from Feed through from BB00DDss*+*+DD*-*- to D to Dss

++--

14.9 ± 1.2%14.9 ± 1.2%


BB00DDss++DD*-*- BB00DDss

*+*+DD*-*-

BF=(7.1 ± 2.4 ± 2.5 ± 1.8*) BF=(7.1 ± 2.4 ± 2.5 ± 1.8*) 10 10--

33

BF=(2.5 ± 0.4 ± 0.5 ± 0.6* ) BF=(2.5 ± 0.4 ± 0.5 ± 0.6* ) 10 10 -2-2

PDG: BF=(9.6 ± 3.4 ) PDG: BF=(9.6 ± 3.4 ) 10 10 -3-3 PDG: BF=(2.0 ± 0.7) PDG: BF=(2.0 ± 0.7) 10 10 -2-2

Yield from the missing mass after background subtraction :Yield from the missing mass after background subtraction :

N(B0N(B0DDss++DD*-*-)): : 628 ± 55628 ± 55 N(B0N(B0DDss

*+*+DD*-*-): ): 195 ± 29 195 ± 29

Efficiency: Efficiency: 32.8 ± 1.8%32.8 ± 1.8% Efficiency: Efficiency: 7.5 ± 1.5% 7.5 ± 1.5%

* * due to BR(Ddue to BR(Dss pp)= 3.6 )= 3.6 0.9%0.9%


BB00DD*-*-andandBB00DD*-*-reconstructionreconstructionExclusively reconstructedExclusively reconstructeddecay chain:decay chain:

Selection criteria:Selection criteria:–R2 < 0.5 second Fox-Wolfram momentR2 < 0.5 second Fox-Wolfram moment–Pt(Pt(D*D* ) > 70 MeV ) > 70 MeV–2.52.5 m(K m(K) ) –2.52.5 m(K m(K)-m(K)-m(K) )

EE>30MeV, 120 < m>30MeV, 120 < m150 MeV150 MeV620 < m(620 < m(00) < 920 MeV/c) < 920 MeV/c2 2 00 constrained constrained

BF(BF(DD**DD00)= (68.3)= (68.3±1.4)%±1.4)%

BF(BF(DD00KK) = ( 3.83) = ( 3.83±0.09 )%±0.09 )% *0 DB

0D

K

0D

K

*0 DB0


ExclusiveExclusiveBB reconstructionreconstruction

2*

2

2 BES ps

m

2* s

EE B

Beam energy known to high precision (~MeV)Define “energy-substituted B mass”:

Observables for exclusively reconstructed B candidatesDefine E:

where E*B is the energy of the B candidate in CMS

where p*B is the momentum of

the B candidate in CMS

Largely uncorrelated variables


BB00 D D*-*- reconstruction reconstruction

±±2.5 2.5

Feed down regionFeed down region

±± 2.52.5

Efficiency: Efficiency: = 27.0 = 27.0 ± 1.0 %± 1.0 %

= 18.8= 18.8±0.9±0.9MeVMeVNev=111 Nev=111 ±12±12

2*

2

2 BES ps

m

2* s

EE B


Measured BF(Measured BF(BB00 D D*-*-))mmESES)=)= = 2.45 = 2.45 0.18 MeV/c0.18 MeV/c22

Observed Yield: 119 Observed Yield: 119 11 events11 events

BF (BF (BB00 D D* -* - ++)) = = (3.1 (3.1 0.3 0.3 0.3 ) 0.3 ) 10 10 –3–3

PDG 2000: BF (PDG 2000: BF (BB00 D D* -* -++)) = = (2.76 (2.76 0.21) 0.21) 10 10 –3–3


N N BBBB 3.63.6

Track efficiencyTrack efficiency 7.57.5

Soft pion efficiencySoft pion efficiency 2.52.5

Selection criteria variationSelection criteria variation 3.03.0

Intermediate BRIntermediate BR 2.02.0

MC statisticsMC statistics 4.04.0

TotalTotal 9.7 %9.7 %

L ~ 5.2L ~ 5.2 fbfb-1-1


BB00 D D*-*-reconstructionreconstruction

Efficiency: = 7.6 ± 0.6 % for D*

= 1.1 ± 0.3 % for D* ±2.5

±2.5

= 40±5 MeV

A Dalitz analysis of D* 0 will be performed on the full data sample.

Upper limit on the non-resonant contribution by CLEO: < 9% at 90% CL.


Measured BF(Measured BF(BB00 D D* -* -++))mmESES)=3.5 )=3.5 0.3 MeV/c0.3 MeV/c22

Observed Yield: 131 Observed Yield: 131 13 evts13 evts

BF (BF (BB00 D D* -* - ++) = (11.5 ) = (11.5 1.1 1.1 2.5) 2.5) 10 10 –3–3

PDG 2000: BF (PDG 2000: BF (BB00 D D** -- ++)) = = (6.8 (6.8 3.4) 3.4) 10 10 –3–3


N N BBBB 3.63.6

Track efficiencyTrack efficiency 7.57.5

Soft pion efficiencySoft pion efficiency 2.52.5

0 0 efficiencyefficiency 5.05.0

Selection criteria variationSelection criteria variation 3.03.0

Intermediate BRIntermediate BR 2.02.0

Selected Selected E range variationE range variation 10.010.0

Two Hemisphere Two Hemisphere helicity angle helicity angle 15.015.0

MC statisticsMC statistics 8.08.0

TotalTotal 22.4 22.4

L~ 5.2 fbL~ 5.2 fb-1-1


Exclusive Reconstruction of Exclusive Reconstruction of BB decays to charm decays to charm

2577±59 B2577±59 B002636±56 B2636±56 B±±

( )

BB00DD*-*-BB00DD*-*-

BB00DD - -BB00DD--BB00DD*-*-aa11

BB00DD--aa11

B B --D D 00B B --DD*0*0


BB00 2S)K2S)K00ss

( )( )

BB00DD*+*+

2S)

KK00ss

DD*+*+DD00DD00KK--


ConclusionsConclusions Preliminary results on BR of hadronic Preliminary results on BR of hadronic

B decays to open charm:B decays to open charm:

BR (BR (BB D DssXX ) ) (11.9 (11.9 0.3 0.3 1.1 1.1 3.0) 3.0) 1010-2-2 (10.0 (10.0 2.5) 2.5) 1010-2-2

BR (BR (BB D Dss* * XX ) ) (6.8 (6.8 0.7 0.7 0.8 0.8 1.7) 1.7) 10 10-2-2

BR (BR (BB00 D Dss+ + DD** --)) (2.6 (2.6 0.4 0.4 0.6 0.6 0.7) 0.7) 10 10-2-2 (9.6 ± 3.4 ) (9.6 ± 3.4 ) 1010-3-3

BR (BR (BB00 D Dss* + * + DD** --)) (7.4 (7.4 2.5 2.5 2.6 2.6 1.9) 1.9) 1010-3-3 (2.0 ± 0.7) (2.0 ± 0.7) 1010-2-2

BR (BR (BB00 D D** ---+-+)) (2.9 (2.9 0.3 0.3 0.3 ) 0.3 ) 10 10 –3–3 (2.76 ± 0.21 ) (2.76 ± 0.21 ) 1010-3-3

BR (BR (BB00 D D** --+ + )) (11.5 (11.5 1.2 1.2 2.5) 2.5) 10 10 –3–3 (6.8 ± 3.4 ) (6.8 ± 3.4 ) 1010-3-3

PDG 2000 valuePDG 2000 value BBAABBARAR Preliminary Preliminary

b decays to d s +() and d +

Documents

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nb0ds d

resonanceben brau dpf

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p reconstruction2

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inclusive reconstruction

b decays to d s +(*) and d *+

b decays to d s +() and d +