B hadron masses and branching ratios at CDF

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B hadron masses and branching ratios at CDF

• Saverio DAuria, University of Glasgow
• For the CDF collaboration

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Contents

• Trigger types at CDF
• Masses at CDF
• Results on mass measurements
• B?,B0
• Bs
• Lb
• Branching fractions at CDF
• Results on branching fractions
• Bs ? Ds p
• Lb ? L p
• B ? hh-
• Conclusions and prospective analyses

Related talks S. Farrington B lifetime and
Flavour tagging at CDF (HF) S. Giagu
Results on CP violation from CDF (CP) J. Thom
Rare Charm decays from CDF (RareDecays) T.
Shears Bottom and Charm quark
production in CDF (QCD) C. Ginsburg CDF
run-II muon detector system (DDH) G. Bolla
Commissioning, operations and first results
of the CDF run-II-a Silicon (DDH)
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Introduction
Integrated Luminosity
Used in this analysis COT tracking chamber,
XFTrigger ?(1/pT) 0.1 GeV 1
?(hit)150?m dE/dx K-p separation is 1.3 s at pt
gt 2GeV/c Silicon detector, SVTrigger 5 Layers,
i.p. resolution 30 mm, SVT
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Trigger types

• B-Physics at CDF is based on 3 trigger types
• di-lepton trigger (J/Y)
  
• two tracks with d0 gt 120mm (2-Track Trigger)
• lepton track with impact parameter gt 120mm
  (leptonSVT)

Used here
SVT 33mm beam ? 35mm res.
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Masses at CDF
The di-lepton trigger has a large statistics of
fully reconstructed B decays Mass scale
calibrated on J/Y, check performed on Y and Y(1S)
dE/dx use GEANT description Material
adjustment Magnetic field 0.165
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Mass measurements results
Analysis cuts J/Y mass window 80 MeV K0 mass
window 80 MeV Decay length (B) gt100 mm Pt
(B) gt 6.5 GeV
Analysis cuts J/Y mass window 80 MeV Pt(K)
gt 2 GeV Decay length (B) gt100
mm Pt (B) gt 6.5 GeV
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Mass measurements results
Analysis cuts J/Y mass window 80 MeV L mass
window 15 MeV Decay length (Lb) gt100
mm Pointing cut cos qBgt 0.95
Analysis cuts J/Y mass window 80 MeV F mass
window 10 MeV Decay length (Bs) gt100
mm Pt (Bs) gt 6.5 GeV
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Mass measurements summary
MeV
Main sources of systematic errors

• Prospects
• what can we do with more statistics
• Systematic error will decrease correct for
  smaller effects
• Statistical error will scale with integrated
  Luminosity mass differences
• Mass of other Meson, Baryons will be measured.

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Branching fractions at CDF

• Ratios of Branching Fractions
• Uncertainties on b cross section ( 9 c.m.
  Energy)
• Systematic effects on trigger efficiency
• Rely on other measurements for
• Production fractions fx? allow for measurement
  in future
• Branching ratio of control mode
• Branching fractions to daughters daughters
• Fully reconstructed decays from the Two-Track
  Trigger stream

e.g.
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Branching Fractions
?
Normalization decay mode Bd ? D p?

• Same mode for
• D peak also visible.

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Branching Fractions
First measurement Bs ? Ds p?
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Branching Fraction Bs ? Ds p?
Results
From MC R 1.08 ? 0.02
From PDG Rbr 2.53 ? 0.65
From data fit NBs 44 ? 11 (stat) ? 7
(sys) NB0 505 ? 44 (stat) ? 20 (sys)
BR(Bs ? Ds p?) ( 4.8?? 1.2?? 1.8?? 0.8?? 0.6)
?10-3
(Stat) (BR) (sys) (fs/fd)
New measurement ! Previous limit set by OPAL BR
(Bs ? Ds p? ) lt 13
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Branching Fractions
First measurement Lb ? Lc p?? p K p p

• Reflections take a p for a p and
• the control channel B0?(K p p) p
• has a reflection peak right under the
• signal.
• Use MC to parametrise the shape.
• Use data to normalize the amplitude
• Take into account into fitting function

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Branching Fraction Lb ? Lc p?
Results
From MC R 1.20 ? 0.02
From PDG Rbr 1.82 ? 0.49
From data fit NLb 96 ? 13 (stat) 6 7
(sys) NB0 321 ? 22 (stat) ? 20 (sys)
New Result !
Previous observations Delphi 3 evts Aleph 4 evts
BR(Lb ? Lc p?) (6.5 ?1.1(stat) ? 0.9(sys) ?
2.3(BR,f) ) 10-3
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Branching Fractions B? h h() -

• required to be trigger tracks.
• Optimise offline Cuts on MC signal, data
  sideband

• Isolation
• Efficiency from data

• Defined in a cone about the B axis

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Branching Fractions B? h h() -
Different signal contributions
Monte Carlo

• Total width due to several different
  contributions.
• on top of each
  other
• Disentangle using
• Invariant Mass
• Relative momentum
• PID

Kinematic Separation
? Most Important
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Branching Fractions B? hh() -
Kinematic separation

• Choose 2 variables

Monte Carlo

• Signal Likelihood

? Gm1,s1(ID1) ?Gm2,s2(ID2)
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Branching Fractions B? hh() -
Present Results
Consistent with no CPV
Using B-factories average for BR(Bd?Kp) (18.5
? 0.1) ?10-6 We obtain BR(Bd?pp-) (4.81 ?
2.05 ? 1.02) ?10-6
Heavy Flavor Averaging Group
Yields
Ratio of B-factories average
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Branching Fractions forthcoming channels
e.g. B??f K?
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Conclusions

• Mass and Branching ratio techniques in CDF are
  well established
• new channels are now available thanks to
  improved trigger (SVT)
• Most precise measurement of Lb and Bs mass
• New branching ratios have been measured
• Bs? Ds p and
• Lb?Lc p?
• BR sensitivity O(5 ?10-6) with present data.
• We have just opened the lid a large number of
  new measurements
• will be performed in the near future.