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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 - PowerPoint PPT Presentation
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Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDF
B hadron masses and branching ratios at CDF
Saverio D’Auria, University of Glasgow
For the CDF collaboration
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFContents
• Trigger types at CDF• Masses at CDF• Results on mass measurements:
- B,B0 - Bs
- b
• Branching fractions at CDF• Results on branching fractions:
- Bs Ds - b - 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)
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFIntroduction
Used in this analysis:COT tracking chamber, XFTrigger
(1/pT) ~ 0.1% GeV –1; (hit)~150m
dE/dx K- separation is 1.3 at pt > 2GeV/cSilicon detector, SVTrigger: 5 Layers, i.p. resolution 30 m, SVT
Integrated Luminosity
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFTrigger types
B-Physics at CDF is based on 3 trigger types:• di-lepton trigger (“J/”) • two tracks with d0 > 120m (“2-Track Trigger”)• lepton + track with impact parameter > 120m (“lepton+SVT”)
}Used here
SVT: 33m beam 35m res.
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFMasses at CDF
The di-lepton trigger has a large statistics of fully reconstructed B decaysMass scale calibrated on J/, check performed on ’ and Y(1S)
dE/dx: use GEANT descriptionMaterial adjustmentMagnetic field: +0.165%
CDF mass PDG mass
’ 3685.80 0.12
3685.96 0.09
Y(1S) 9461.1 1.5 9460.30 0.26
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFMass measurements: results
Analysis cuts:J/ mass window: ±80 MeV mass window: ±80 MeVDecay length (B): >100 mPt (B) > 6.5 GeV
Analysis cuts:J/ mass window: ±80 MeVPt±) : > 2 GeVDecay length (B): >100 mPt (B) > 6.5 GeV
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFMass measurements: results
Analysis cuts:J/ mass window: ±80 MeV mass window: ±15 MeVDecay length (b): >100 mPointing cut: cos B> 0.95
Analysis cuts:J/ mass window: ±80 MeV mass window: ±10 MeVDecay length (Bs): >100 mPt (Bs) > 6.5 GeV
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFMass measurements: summary
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.
Mass (MeV/c) Best single meas. PDG
PDG value
B+ 5279.32 0.68 0.94
5279.1 0.4 0.4 5279.0 0.5
B0 5280.30 0.92 0.96
5279.1 0.7 0.3 5279.4 0.5
Bs 5365.50 1.29 0.94
5369.9 2.3 1.3 5369.6 2.4
b 5620.4 1.6 1.2 5621 4 3 5624 9Mass constrained fit 0.8
B-field corrections 0.2
dE/dx corrections 0.2
Alignment/tracking 0.4
Main sources of systematic errors MeV
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching fractions at CDF
0 0
0 0
0
0
( )( )
( ) ( )d b
b d
Bb baryon b c
b d d cB
N BR D Kf BR
f BR B D N BR pK
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
e.g.
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDF
• Same mode for:
• D* peak also visible.
0S SB D
0b c
Branching FractionsNormalization decay mode: Bd D
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDF
First measurement: Bs Ds Branching Fractions
1.013 1.028K K
m GeV
sD
4t sp D GeV
2D-Dist Prim 400sD m
2D-Flight-Dist 100sB m
Impact-Par 100sB m
4t sp B GeV
Analysis Cuts:
2 Tracks required to be Trigger Tracks.
mass constrained to
PDG value
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fraction: s Ds
Results:
)()(
)()(
)(
)(
0
0
0
sB
sB
s
ss
d
s
DBRKDBR
N
N
BB
DBBR
DBBRff
From MC: R = 1.08 0.02
From PDGRbr = 2.53 0.65
)(07.0)(11.0)(11.044.0)(
)(0 BRsysstat
DBBR
DBBRff ss
d
s
From data fit:
Ns = 44 11 (stat) 7 (sys)NB0 = 505 44 (stat) 20 (sys)
New measurement !Previous limit set by OPAL: BR (Bs Ds ) < 13%
BR(Bs Ds ) = ( 4.8 1.2 1.8 0.8 0.6) 10-3 (Stat) (BR) (sys) (fs/fd)
From PDG: 0.273 0.034 :s
d
f
f
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDF
First measurement: b c p K
Branching Fractions
“Reflections”: take a for a p and
the control channel B0(K 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
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fraction: b c
Results:
)()(
)()(
)(
)(
0
0
0
pKBRKDBR
N
NB
DBBR
BRff
cB
b
b
cb
d
b
From MC: R = 1.20 0.02
From PDGRbr = 1.82 0.49
)(18.0)(09.0)(11.066.0)(
)(
0BRsysstat
DBBR
cbBR
dfb
f
From data fit:
Nb = 96 13 (stat) +6 –7 (sys)NB0 = 321 22 (stat) 20 (sys)
New Result ! Previous observations:Delphi 3 evtsAleph 4 evts
BR(b c ) = (6.0 1.0(stat) 0.8(sys) 2.1(BR) ) 10-4
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDF
• required to be trigger tracks.
• Optimise offline Cuts on MC signal, data sideband:
Branching Fractions: B h+ h(’) -
h h
1 2 5.5t tp p GeV
1 2, 150IP IP m
2D-Flight-Dist 300B m
80BIP m
• Isolation:
•Efficiency from data
tB daughters
tAll Tracks
p
Ip
•Defined in a cone about the B axis:
/B J K
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fractions B h+ h(’) -
dE
dx
• Total width due to several different contributions.
• on top of each other
• Disentangle using:
• Invariant Mass
• Relative momentum
• PID
,d sB B K K PID essential
← Most Important
{Kinematic Separation
Monte Carlo:
Different signal contributions:
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fractions B h+h(’) -
• Choose 2 variables:
• Signal Likelihood:
dB
0 /dB K K 0 /dB K K
/sB K K sB K K
/sB K K
M
11
2
1p
qp
1 2where: p p
Monte Carlo:
Kinematic separation:
G1,(ID1) G2,(ID2)
)()(
2
1exp
2
12
PMM
F
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fractions B h+h(’) -
0
0
( )0.26 0.11( ) 0.055( )
( )d
d
BR Bstat syst
BR B K
Yields:
0dB K
0dB
0sB K
0sB KK
3 11(stat)
90 17(stat)
148 17(stat)
39 14(stat)
Ratio of B-factories average:
Present Results:
)(017.0)(15.002.0)( sysstatKAdirCP
03.026.0)(
)( 0
BBR
BBR d
Consistent with no CPV
Using B-factories average for BR(Bd) = (18.5 0.1) 10-6
We obtain:BR(Bd) = (4.81 2.05 1.02) 10-6
[Heavy Flavor Averaging Group]
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFBranching Fractions: forthcoming channels e.g.
Saverio D’Auria CDF International Europhysics Conference on High Energy Physics, Aachen, July 17 2003
CDFConclusions:• Mass and Branching ratio techniques in CDF are well established:
new channels are now available thanks to improved trigger (SVT)
• Most precise measurement of b and Bs mass
• New branching ratios have been measured: Bs Ds and bc
• 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.