xin chen, baosen cheng, mousumi datta, haibo li, bruce mellado and sau lan wu university of...
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Xin Chen, Baosen Cheng, Mousumi Datta, Haibo Li, Bruce Mellado and Sau Lan Wu
University of Wisconsin-Madison
BReco Meeting 07/08/04
Update on Searches for Charmed Pentaquarks in B0-
>D(*)pp()
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Outline
Reconstruction Modes and Pre-selection cuts (Beta code)Overview of pentaquark searches
Invariant mass spectra
Upcoming analyses
Outlook and Plans
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Reconstruction ModesB0 decays involving D, proton, which may be used for charmed pentaquark searches1. B0->D*ppbar, D*->D0, D0->K,K3,K0,Ks
2. B0->Dppbar, D->K,K0,Ks,Ks0
3. B0->D*0ppbar, D*0->D00, D0->K,K3,K0,Ks4. B0->D0ppbar, D0->K,K3,K0,KsXin Chen reports today on branching ratios for channels 1-4 with 112.55 fb-1 of data (Run I-III)Here we report pentaquark searches and study of ppbar invariant mass spectra with 112.5 fb-1
for decay channels 1-4 Most of recent efforts have gone to understanding better branching ratios extraction
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Overview of Pentaquark
Searches
Same minimal quark content as in direct combination of channels 3-4 (cbaruuud) may be obtained with D*-(D-)p+ in channels 1-2
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Pre-Selection
1.Both Proton and anti-proton from pLhVeryLoose2.K (D daughter) from KMicroNotPion3. from GoodTracksVeryLoose4. 0 from Pi0AllDefault5.Ks from KsDefault6. (from B) from ChargeTracks7.D0 mass window: 40 MeV (70 MeV for decays with 0 )
8.D mass window: 70 MeV9.MES>5.2 GeV and |E|<0.4 GeV 10.Vertex convergence for B0, D0 and D- candidates
Cuts at Beta code level based on MC only
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Final Cuts
Subdivided into channel independent and channel dependent cuts
Coupled to branching ratio extraction analysis
Documented in BAD 916 (branching ratio extraction analysis)BAD 997 to be submitted today
Continuation of BAD 916
Today’s talk by Xin Chen
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Constrained Mass for Channels 1-2
D0->K
D0->K3
D0->K0
D-->K- + +
Channel 1 (B0->D*ppbar, D*->D0)
Channel 2 (B0->Dppbar)
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Constrained Mass for Channels 3-4
D0->K
D0->K3
D0->K0
Channel 2 (B0->D*0ppbar, D*0->D00)
Channel 4 (B0->D0ppbar)
D0->K
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cduud (direct combination)
Channel 1
Channel 2
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cduud (indirect combination)
Channel 1
Channel 2
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cuuud (direct combination)
Channel 3
Channel 4
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cuuud (indirect combination)
Channel 4
Channel 3
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Dalitz for Chanels 3-4
Channel 3
Channel 4
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cuuud (direct combination)
Channel 1
Channel 2
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cuuud (indirect combination)
Channel 1
Channel 2
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Upcoming Analyses
Need to look more into D*0(D0)p invariant mass spectraExclusive decays (not observed before)
B-->D*0ppbar- (plus c.c.) B-->D0ppbar- (plus c.c.) Beta Ntuples have been generated. To be analyzed Hard for a 4 GeV resonance due to lack of phase
spaceInclusive analysis
D*0p (plus c.c.) D0p (plus c.c.) Beta Ntuples have been generated. To be analyzed
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Outlook and Plans
Search of a charmed pentaquark in B0->D(*)ppbar() decays is reaching maturityBAD 916 v5 with details on branching ratio (for all 4 B
decays) has been submitted Will submit BAD 997, continuation of BAD 916 with
details of pentquark analysisIn channels 1 and 2 Dp invariant mass spectra do not
show significant deviation from phase-space hypothesis
Channels 3 and 4 display differences between D0*barp (direct combination) and D0*p (indirect combination) invariant mass spectra, inconsistent with MC prediction Will start looking into
Exclusive decays B-->D*0ppbar-, B-->D0ppbar- (plus c.c.) Inclusive D*0p and D0p (plus c.c.)