Post on 09-Feb-2019
SB0 0bΛandBranching Ratios from
Matthew MartinJohns Hopkins University
for the CDF collaboration
Flavor Physics & CP ViolationEcole Polytechnique, Paris, France
June 2003
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Outline:• Motivation• Branching Ratios at CDF• Results from:
B h h+ −− →
0S SB D π− +− →
0b c π
+ −− Λ →Λ
• Conclusions
M.Martin, Johns Hopkins for CDF, FPCP June 2003
CDF plans a rich program of B-Physics:
• Precision study of the :– BR’s, mass and lifetime– Plan to observe or rule out SM mixing– Measure – Measure
• The world’s largest sample:– BR’s, mass and lifetime– CP Violation searches
• This program just beginning…
0bΛ
0SB
SB∆Γ
0SB
γ
M.Martin, Johns Hopkins for CDF, FPCP June 2003
What we know: 0SB
PDG 2002:
New results for:
0S sB D π− +→
0SB K K+ −→
NEW !
NEW !
M.Martin, Johns Hopkins for CDF, FPCP June 2003
What we know: 0bΛ
PDG 2002:
NEW !
Nearly New results for: 0b c π
+ −Λ → Λ
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Hadronic Level 2 Trigger:
-500 -250 0 250 500silicon trigger impact parameter (µm)
Trac
ks p
er 1
0 µm
0
40
00
80
00
0 10 20 30 40 50Silicon trigger latency (µs)
Even
ts p
er 0
.5 µ
s0
1000
0
200
00
35µm ⊕ 33µmresol ⊕ beam⇒ σ = 48µm •Interaction rate
•Reduced to on Level 2 output.
•Critical component : SVT impact parameter cuts.
•2 Tracks with
2.5MHz
300Hz
120IP mµ>
~~
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Branching Ratios at CDF:• Compare search mode to kinematically similar mode, eg:
• Cancellation:
– Systematics in Trigger and Reconstruction Efficiency.• Production fractions ( ):
– LEP/CDF Combined.– Aim to measure at CDF.
• Daughter BR’s :– Rely on existing measurements.– Future : CLEO-C
• Plan to normalise to same channel Semileptonic
0 0
0 0
0
0
( )( )( ) ( )
d b
b d
Bb baryon b c
b d d cB
N BR D Kf BRf BR B D N BR pK
ε π πσ πσ π ε π
− − + ++ −Λ
+ − + − +Λ
× × →× × Λ →Λ=
× × → × × Λ →
bσ−
f
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Normalisation mode:
Candidate Mass (GeV)4.6 4.8 5 5.2 5.4 5.6
even
ts (
10 M
eV/b
in)
0
50
100
150
200
250
300
April 3rd 2003 CDF Run 2 PRELIMINARY-1 4 pb±65
+π -(*) D→dB-π -π + K→-D
and c.c
44 events± Yield: 505 - D
0.002 GeV± Uncorr. Mean: 5.267
2 MeV± Sigma: 23
• Same mode for:
• Similar cuts to signal
• also visible.
0dB D π ±→ m
0S SB D 𠱕 → m
0b c π
+ −• Λ → Λ
*D
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Reconstructing:
Candidate Mass (GeV)4.6 4.8 5 5.2 5.4 5.6 5.8
even
ts (
20 M
eV
/bin
)
0
5
10
15
20
25
30
35
40
April 3rd 2003 CDF Run 2 PRELIMINARY-1 4 pb±65
sD*sD
π (*)s D→sB
π ϕ →sD KK→ ϕ
11 events± Yield: 44 sD
5 MeV±Uncorr. Mean: 5361
4 MeV±Sigma: 20
0S SB D π ±→ m
( )1.013 1.028K Km GeV+ −• < <
sD•
( ) 4t sp D GeV• >
( )2D-Dist Prim 400sD mµ• → >
( )2D-Flight-Dist 100sB mµ• >
( )Impact-Par 100sB mµ• <
( ) 4t sp B GeV• >
Important Cuts:2 Tracks required to be Trigger Tracks.
mass constrained to
PDG value
•
First Observation!
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Systematics:s
d
B
B
NN
σ
0.008±
0.008±sB
dB
ParticleUncertainty in due to fit.sB
N←dB
N
( )/s dB Bσ ε εSource
s
d
B
B
εε
← Uncertainty in0.001+XFT 1-miss( )Due to MC
0.08− − − −Min b quark tp
0.02 0.04− +B lifetimes
0.00 0.04+D lifetimes BR Total Syst: 0.07±Total 0.08 0.06− +
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Results:( )
0.44 0.11( ) 0.11( ) 0.07( )( )
s s s
d d
f BR B Dstat BR syst
f BR B Dππ
× →= ± ± ±
× →
From PDG: 0.273 0.034 :s
d
ff= ±
( ) 1.61 0.40( ) 0.40( ) 0.26( ) 0.20( )
s s s
d d
BR B D fstat BR syst PDGBR B D f
ππ
→= ± ± ± ± →
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Reconstructing 0b c π
+ −Λ →Λ
Important cuts:
( ) 2tp P GeV• >
( )0from 2t bp GeVπ• Λ >
( )0 225bct mµ• Λ >
( )0from 65c bct mµ• Λ Λ > −
( )0Impact-Par 100b mµ• Λ <
( )( )2.265 2.303cm GeV• < Λ <
Confirm Trigger•
( ) 4.5t cp GeV±• Λ >
( )0 7.5t bp GeV• Λ >
M.Martin, Johns Hopkins for CDF, FPCP June 2003
b Reflections:
•3 Types of reflection:
•4-Prong Decays
(eg )
•Other decays
•Everything else.
•Normalise Reflection shape to measured
yield.
0dB D π ±→ m
0bΛ
0dB D π ±→ m
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Expected Systematics:
Total 6 5+ −
( )Size %SourceB lifetime negligible
0 lifetimebΛ 4 5+ −
Dalitz structurecΛ 1±1+b spectrumtp
2±0 , polarisationb cΛ Λ
XFT 1 miss 3+3+Phi efficiency
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Current Status:• Finalising reflection model
0
0
( )( )
baryon b c
d d
f BRf BR B D
ππ
+ −
+ −
× Λ →Λ
× →• measurement for EPS
• Systematic uncertainty dominated by:
( )( ) 25%cBR pKσ π+ − +Λ → ~
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Prospects for improving normalisation:
]2
)[GeV/cππM(K
1.7 1.8 1.9 2
2E
ven
ts/5
MeV
/c
0
100
200
300
400
500
600X-D+µ →B
60±) = 2061 ±
N(D
-1 4 pb± = 65 L dt ∫CDF Run II Preliminary
]2
)[GeV/cπ)-M(KππM(K
0.14 0.145 0.15 0.155 0.16
2E
ve
nts
/0.2
Me
V/c
0
20
40
60
80
100
120X*-D+µ →B
-π0 D→ 27±) = 707
±*N(D
-1 4 pb± = 65 L dt ∫CDF Run II Preliminary
Note : Hadronic Trigger Path
M.Martin, Johns Hopkins for CDF, FPCP June 2003
B h h+ −→• required to be trigger tracks.
• Optimise offline Cuts on MC signal, data sideband:
h h+ −
1 2 5.5t tp p GeV• + >
( )1 2, 150IP IP mµ• >
( )2D-Flight-Dist 300B mµ• >
80BIP mµ• <
• Isolation:
•Efficiency from data
tB daughters
tAll Tracks
pI
p−=∑∑
•Defined in a cone about the B axis:
( )/B J Kψ± ±→
Reconstructing
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Different signal contributions:
dEdx
• Total width due to several different contributions.
• on top of each other
• Disentangle using:
• Invt Mass
• Relative momentum
• PID
,d sB B K Kππ→ →PID essential⇒
← Most Important
{KinematicSeparation
Monte Carlo:
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Kinematic separation:• Choose 2 variables:
• Signal Likelihood:2( )1 1exp ( )
22M MF Pππ α α
σπσ
− = −
dB π π→
0 /dB K Kπ π+ − − +→ 0 /dB K Kπ π− + + −→
/sB K Kπ π− + + −→sB K K→
/sB K Kπ π+ − − +→
Mππ•
11
2
1 p qp
α
• = −
1 2where: p p<
Monte Carlo:
M.Martin, Johns Hopkins for CDF, FPCP June 2003
• calibrated on sample
• Bachelor charge identifies daughters.
π0D
( ) ( )( ) ( )( )2
1, 1,1 1exp 1 2
22
ij jj
i j jii
M MF P G ID G IDππ αµ σ µ σα
σσ π
− = −
dEdx
*D
/dE dxParticle ID :
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Systematics:
/dE dx +0.05 -0.05 +0.01 -0.01*
+0.005 -0 .006
d
d
BB K
πππ
→→
( )dirC PA Kπ
BC K Shape +0.019 -0.015 +0.002 -0.009
( )dM B +0.0003 -0.0003+0.004 -0.004
( )sM B +0.002 -0.003
( )Mσ +0.004 -0.009 +0.006 -0.005
M C stat +0.002 -0.002 +0.007 -0.007
* new calibration will reduce systematic
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Current Results:0
0
( ) 0.26 0.11( ) 0.055( )( )
d
d
BR B stat systBR B K
πππ
→= ± ±
→
( )dirCPA = 0.02 0.15(stat) 0.17(syst)Kπ ± ±
Yields:
0dB Kπ→
0dB ππ→
0sB Kπ→
0sB KK→
3 11(stat)±
90 17(stat)±
148 17(stat)±
39 14(stat)±
PDG 2002:0
0
( ) 0.13 0.010.29 0.12 0.02( )d
d
BR BBR B K
πππ
→ + += − −→
M.Martin, Johns Hopkins for CDF, FPCP June 2003
Conclusions:
• First measurement of relative BR • First observation of
– Measurement of validates extraction procedure
• Expect and for EPS• First steps toward an exciting programme in
physics and physics (mixing and CPV) .0bΛ
0SB
• CDF has robust signals in:0b cπ
+ −Λ →Λ0S SB D π±→ m
sB K K→••
•
0S SB D π ±→ m
sB K K→0
0
( )( )
d
d
BR BBR B K
πππ
→→
0b c π
+ −Λ →ΛsB K K→