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1-2/2
1-2/2
u
c
d s b
A 3(1--i) -A2t
d, sb
d, s b
Vtd ,VtsB Oscillations
A 3(i)
A2
1Vtb
c,u
B decays
b
Vub,Vcb
Wolfenstein parametrization 4 parameters : ,A,
The CKM matrixThe CKM matrix
2Theory
Experiments at the Z / Experiments at the Z / ((4S4S))
3
pB ~ 1 GeV
pB ~ 30 GeV
Z Z bbbb
(4S)(4S) BB BB
CLEOALEPH
DELPHI
OPAL
BABAR
The DELPHI experiment
pB ~ 0.3 GeV
BELLE
~ 150~ 150 MM
~ 3.4~ 3.4 MM
~ 0.8~ 0.8 MM
4
Event SelectionEvent Selection
Analysed data samples
Lifetime probability
5
Event ReconstructionEvent Reconstruction
Analysed data samples
D mass resolution
Decay distances
6
Discriminant variablesDiscriminant variables
Analysed data samples
~80%~80% ~80%~80%
~80%~80%~46%~46%
QX< 0 QX= 0 23
13
qq2 2 measurementmeasurement
7|Vcb| from
qq2 2 measurementmeasurement
8|Vcb| from
FitFit
9|Vcb| from
Event by event Event by event likelihood:likelihood:
P(q2) P(m)
P(d+) P(d-)
+ Constraints on Nj (except for combinatorial
and D** backgrounds)
Nsignal ddq2
dq2
dNdq2
|Vcb|2 F2(w) K(w)
eff(q2) res(q2) F(w) as function
of the f.f. 2, R1 and R2.Fit F(1)|Vcb| and 2
meas.
Results on simulated eventsResults on simulated events
10|Vcb| from
Generator level Reconstruction level
11|Vcb| from
Results on individual samplesResults on individual samples
Results on individual samplesResults on individual samples
12|Vcb| from
Fixing the BR = (0.67 ± 0.08 ± 0.11)%
DELPHI averageDELPHI average
13|Vcb| from
DELPHI average:DELPHI average:
Results:Results:Increased statistics ( 4)New channel (K- +(0))
Improvements in the reconstruction (Eb, mD*)
Control on background
New observablesNew measurements
Results on Real Data Results on Real Data
14|Vcb| from
Systematic uncertainties Systematic uncertainties
15|Vcb| from
External External parameters parameters K-+X rates: b fragmentation:
Systematic uncertainties Systematic uncertainties
16|Vcb| from
Detector Detector performance performance
Resolution function:
Syst. due to the parameterization:
F(1)|Vcb|2
2.0% 5%
F(1)|Vcb|2
1.0% 3.5%
Including/excluding
K-+ (0)
Systematic uncertainties Systematic uncertainties
17|Vcb| from
Detector Detector performance performance
d±
distributions:
Systematic uncertainties Systematic uncertainties
18|Vcb| from
Signal and background modelling Signal and background modelling
Signal:
Systematic uncertainties Systematic uncertainties
19|Vcb| from
Background modelling Background modelling
D*2
D*1
D1
Model 1 Model 2
q2sim q2sim
Comparison with other measurementsComparison with other measurements
20|Vcb| from
21
SystematicsSystematics
|Vcb| from
Probability distributionsProbability distributions
22D** properties
Probability distributionsProbability distributions
23D** properties
RD/MCRD/MC
24D** properties
Discriminat variablesDiscriminat variables
25D** properties
Discriminat variablesDiscriminat variables
26D** properties
Discriminat variablesDiscriminat variables
27D** properties
Cascade correction factorsCascade correction factors
28D** properties
SystematicsSystematics
29D** properties
R*
Backgr. mass distribution RD/MCBackgr. mass distribution RD/MC
30D** properties
= 0.5 0.2
i = 3, 5
Non-resonant contributionNon-resonant contribution
31D** properties
D** properties 32
Non-resonant contributionNon-resonant contribution
= 0.42%
H.-Y. Cheng et al. PRD48 (‘93) 3204
DD contribution contribution
33D** properties
EfficienciesEfficiencies
34D** properties
Fit Fit m wrong sign candidatesm wrong sign candidates
35D** properties
Fit Fit m RS cand. for 0.25 < R < 0.70m RS cand. for 0.25 < R < 0.70
36D** properties
DDss spectroscopy spectroscopy
37D** properties
OPE formalismsOPE formalisms
38
11, , 22
, , GG
11, , 22,, i (i=1,4)i (i=1,4)
DD ,, LSLS
Energy of light quarks and gluons (related
with mmbb, m, mcc )
11 ( ) Kinetic energy of the b quark inside
the meson
22 (GG) = chromo-magnetic coupling
(MB*-MB)
22
22
22 22
33 33
|Vcb| from inclusive decays
Pole mass expansionPole mass expansion
Kinetic mass (Kinetic mass (=1GeV)=1GeV)
Can be measured
Spectral momentsSpectral moments
39|Vcb| from inclusive decays
Inclusive observables Inclusive observables O O
CLEO
CO
NF 9
8-2
1
PRL 87 251807 ’01PRL 87 251808 ’01
PDG2002
|Vcb|=(40.8 0.5 2.5) 10-3
|Vcb|=(40.4 0.5 0.5 0.8) 10-3
CLEOCLEO
PDG2000
= (0.35 ±0.07±0.10) GeV 1=(-0.236 ±0.071±0.078) GeV2
Photon and lepton energy (E, El),Mass hadronic distribution (Mx), ...
ssbb
q2
ccbb
Expressed in terms Expressed in terms of the same of the same theoretical theoretical parametersparameters
Moments of the Moments of the D** D** distributiondistribution
40|Vcb| from inclusive decays
Inclusive b semileptonic decays
@ LEP
78% Bd , B- 22% Bs , b
22% D 50% D*
28% D**
Exclusive processes
Moments of the total hadronic mass distribution in bc -
Inclusive decay width determination
Study of D** properties
Known
Systematics on momentsSystematics on moments
41|Vcb| from inclusive decays
Combining information on momentsCombining information on moments
Moments
Moments of the lepton energy spectrum by DELPHI
(DELPHI 2002-070-CONF-604)
Combined fit to the 3 first moments
of hadronic and leptonic moments
Two formalismsmmqq
polepole
mmqqkin kin (q)(q)
Included s and (1/mb)3 corrections
Constraints from external results
2 fit to 6 moments
s = 0.22 ± 0.01
42
Pole mass formalismPole mass formalism
43Moments
Fixing
Constraints from
and
= 0.35 ± 0.07 ± 0.10 GeV1 = - 0.238 ± 0.071 ± 0.078 GeV2
= 0.53 ± 0.09 GeV1 = - 0.36 ± 0.09 GeV2
BABARBABAR
CLEOCLEO
Comparison with other measurementsComparison with other measurements
44Moments
|Vcb| (inclusive)
Control on non-perturbative corrections up to O(1/mb) 3
Well defined scheme
Remaining perturbative corrections ~ 1 %
Error of |VError of |Vcbcb| ~ | ~ 2%2%
Updated results Updated results
|Vcb| from moments 45
Using the numerical expression of the Using the numerical expression of the slsl advised by N. Uraltsev :advised by N. Uraltsev :
New moment expressions by P. Gambino :New moment expressions by P. Gambino :
|Vcb| from moments 46
BPS limitBPS limit
Allows an accurate extraction of
N. Uraltsev
(Bogolmo’nyi-Prasad-Sommerfeld)
47Moments
The bThe b quark mass quark mass
Ph.D. M.J. Costa
Ph.D. P. Tortosa
This result
Summary and conclusions Summary and conclusions
48Summary and conclusions
|Vcb| from
Competitive with LEP, CLEO and Competitive with LEP, CLEO and bb--factoriesfactories
Errors of |VErrors of |Vcbcb| dominated by the | dominated by the theorytheory
Improves the previous result from Improves the previous result from DELPHIDELPHI
Large dispersion between results from several Large dispersion between results from several experiments experiments Need for more measurements Need for more measurements
Measurement of Measurement of bb s.l. decays to higher mass states s.l. decays to higher mass states
Need measurements of form factors, production rates, Need measurements of form factors, production rates, BR’s… BR’s…
Summary and conclusions Summary and conclusions
49Summary and conclusions
D** properties
Measurement of the production rates of D**Measurement of the production rates of D**
Study of the D** mass distributionStudy of the D** mass distribution First determination of DFirst determination of D11* properties in B s.l. decays* properties in B s.l. decaysCompatible results of DCompatible results of D00* properties* properties
Measurement of the 3 first moments of the hadronic Measurement of the 3 first moments of the hadronic massmass distributiondistributionFirst measurements at low pFirst measurements at low pCompatible result with CLEO and BABAR Compatible result with CLEO and BABAR check OPE check OPE consistencyconsistency
Increased stat., improved Increased stat., improved syst. syst. D** D** DD production limits production limits
|Vcb| from the inclusive decay width
Accurate determination of |VAccurate determination of |Vcbcb||
Development of the kinetic mass schemeDevelopment of the kinetic mass scheme
Combined fit to 6 DELPHI momentsCombined fit to 6 DELPHI moments
Quark masses determinationQuark masses determination
Proximity to the BPS limitProximity to the BPS limit
Control of non-perturbative parametersControl of non-perturbative parameters
50Summary and conclusions
Summary and conclusions Summary and conclusions
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