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B hadron masses and branching ratios at CDF

B hadron masses and branching ratios at CDF. Saverio D’Auria, University of Glasgow For the CDF collaboration. Contents. Trigger types at CDF Masses at CDF Results on mass measurements: B  ,B 0 B s L b Branching fractions at CDF Results on branching fractions: B s  D s p

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B hadron masses and branching ratios at CDF

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  1. B hadron masses and branching ratios at CDF Saverio D’Auria, University of Glasgow For the CDF collaboration International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  2. 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 Dsp • Lb  Lp • B  h+h- • 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) International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  3. 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 > 2GeV/c Silicon detector, SVTrigger: 5 Layers, i.p. resolution 30 mm, SVT International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  4. Trigger types • B-Physics at CDF is based on 3 trigger types: • di-lepton trigger (“J/Y”) • two tracks with d0 > 120mm (“2-Track Trigger”) • lepton + track with impact parameter > 120mm (“lepton+SVT”) }Used here SVT: 33mm beam  35mm res. International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  5. 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% International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  6. Mass measurements: results Analysis cuts: J/Y mass window: ±80 MeV K0* mass window: ±80 MeV Decay length (B): >100 mm Pt (B) > 6.5 GeV Analysis cuts: J/Y mass window: ±80 MeV Pt(K±) : > 2 GeV Decay length (B): >100 mm Pt (B) > 6.5 GeV International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  7. Mass measurements: results Analysis cuts: J/Y mass window: ±80 MeV F mass window: ±10 MeV Decay length (Bs): >100 mm Pt (Bs) > 6.5 GeV Analysis cuts: J/Y mass window: ±80 MeV L mass window: ±15 MeV Decay length (Lb): >100 mm Pointing cut: cos qB> 0.95 International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  8. 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. International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  9. 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 daughter’s daughters • Fully reconstructed decays from the “Two-Track Trigger” stream Branching fractions at CDF e.g. International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  10. Branching Fractions  Normalization decay mode: Bd D p • Same mode for: • D* peak also visible. International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  11. Analysis Cuts: 2 Tracks required to be Trigger Tracks. mass constrained to PDG value First measurement: Bs Dsp Branching Fractions International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  12. Results: Branching Fraction: Bs Dsp From data fit: NBs = 44 11 (stat) 7 (sys) NB0 = 505  44 (stat)  20 (sys) From MC: R = 1.08  0.02 From PDG Rbr = 2.53  0.65 BR(Bs Dsp) = ( 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 Dsp ) < 13% International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  13. First measurement: Lb Lcp p K p p Branching Fractions • “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 International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  14. Results: Branching Fraction: Lb Lcp 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 Lcp) = (6.5 1.1(stat)  0.9(sys)  2.3(BR,f) ) 10-3 International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  15. 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: International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  16. Different signal contributions: Branching Fractions B h+ h(’)- 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 International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  17. Kinematic separation: Branching Fractions B h+h(’)- Monte Carlo: • Choose 2 variables: • Signal Likelihood:  Gm1,s1(ID1) Gm2,s2(ID2) International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  18. Present Results: Branching Fractions B h+h(’)- Consistent with no CPV Using B-factories average for BR(BdKp) = (18.5  0.1) 10-6 We obtain: BR(Bdp+p-) = (4.81  2.05  1.02) 10-6 [Heavy Flavor Averaging Group] Yields: Ratio of B-factories average: International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  19. e.g. Bf K Branching Fractions: forthcoming channels International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

  20. 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 Dsp and • LbLcp • 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. Conclusions: International Europhysics Conference on High Energy Physics, Aachen, July 17 2003

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