a big success with more than 200 participants
DESCRIPTION
A big success with more than 200 participants. AIM OF THE WORKSHOP. Make an overall status of our knowledge of the CKM parameters at the end of the era of CLEO, LEP, SLD, TeVatron I (reach consensus to start from common base). Try to define priorities for theoretical developments - PowerPoint PPT PresentationTRANSCRIPT
A big success with more than 200 participants
AIM OF THE WORKSHOPMake an overall status of our knowledge of the CKM parameters at the end of the era of CLEO, LEP, SLD, TeVatron I(reach consensus to start from common base)
Try to define priorities for theoretical developmentsand future measurements :- in a short timescale (B-Factories/TeVatron II)- in a longer timescale (bridging today LHC)
Working Group I : Vub, Vcb and Lifetimes
Working Group II : Vtd, Vts
Working Group III : CKM Fits
Lattice Data Group (LDG)Forum on Averaging (for PDG + users)
Talks on : Charm and Kaon Physics
Structure of the Workshop
1-2/2 A 3(i)
1-2/2 A2
A 3(1--i) -A2 1
u
c
t
d s b
bd, s b
Vtd ,Vts
B Oscillationsd, s
Vtb
c,u
B decays
bVub,Vcb
The CKM MatrixIn the Wolfenstein parameterization 4 parameters : ,A,
To be continued atB-Factories and TeVatron
• Theoretical assumptions• Theoretical uncertainties
Possible measurements
Theory UT parameters
Measurements
Measurements
Error Meaning (discussion)Statistical Methods to extract UT parameters
•Analysis Methods•Analysis Systematic
WORKING GROUP I
LifetimesVcb Vub
c,u
B decays
bVub,Vcb
Inclusive Determination of Vcb
b c
l
Vcb
Average by LEP Working Groups
BR sl + b
Vcb
Determination of Vcb limited by theoretical uncertainties …..
The expression of Vcb in the low scale running HQ masses formalism (as an example)*
Can these parameters be determined experimentally ?
Vcb = 0.0415 ( 1 - 0.012 2 0.010 mb + 0.006 s + 0.007
mb
(Fermi movement inside the hadron)
( also named )
2
Vcbmbpert* In “Upsilon expansion” formalism :
From CLEO measurements
Other experiments should perform this analysis …….
Value agreed at the end of the Workshop
Part of theoretical error on Vcb becomes experimental
from the determination of 2and mb
Vcb(inclusive)= ( 40.7 ± 0.7 ± 0.8 ) 10-3
It was ± 2.0 and of theo. origin !
Exclusive Determination of Vcb
)(|)(|||48
222
2wGwFV
Gdwd
cbF
(*). DB vvw
G(w) contains kinematics factors and is known (also 1 and )
F(w) is the form factor describing the B D* transition
At zero recoil (w=1), as MQ F(1) 1
Strategy : Measure d/dw and extrapolate to w=1 to extract F(1) Vcb
Syst. dominated by the
knowledge of the D**
(for LEP)
F(1)
|Vcb
|2
2
F(1)
At the Workshop agreement on F(1) = 0.91±0.04 (Gauss.)
3 determinations
What’s next to improve Vcb
Experimental side:
More and new moment analyses
B-factories can perform both exclusive and inclusive analyses
Theory side :
More work on the theory for the 2 ,mb extraction
Unquenched F(1) calculations
Studies of eventual correlation between inclusive and excluive determinations
Form factors measurements in BD*l
Combing the inclusive and the exclusive measurements :
Vcb = (41.8 ± 1.0 ) 10-3
Challenge measurement from LEP
Inclusive determination of Vub
Using several discriminant variables to distinguish between the transitions :
b c b u
Vub
B Xu l
Results from all the LEP experiments
At the Workshop we agreed on Vub(inclusive) = (4.09 ± 0.46 ± 0.36) 10-3
New determination
Exclusive determination of Vub
B l
Vub = (3.68 ± 0.55 +0.28 (syst.))10-3 (in ISGW2 Model)- 0.37
Vub = (3.68 ± 0.14 +0.21 (syst.)± 0.55(theo.))10-3 - 0.29
Babar
CLEO
Important theoretical uncertainties from different models
NOW, Lattice QCD calculations start to be precise
What’s next to improve Vub
Experimental side:
B-factories can perform inclusive/end-point/exclusive analyses
Theory side :
More work on the theory for the extraction of inclusive/end-point analyses
Lattice QCD calculations for exclusive form factors
Correlations between the different Vub determinations
Correspondence between Dl and B l
All lifetimes of weakly decaying B hadrons have been precisely measured
Very important test of the B decay dynamics
Lifetimes
(B0d) = 1.543 ± 0.015 ps ( 1.0%)
(B+) = 1.658 ± 0.014 ps ( 0.9%)(B0
s) = 1.464 ± 0.057 ps ( 3.9%)(B) = 1.208 ± 0.051 ps ( 4.2%)
Averages from LEP/SLD/Tevatron (+ B-Factories)
The hierarchy was correctly predicted !
(B+)/ (B0) about 5 effect in agreement with theory
(B0s)/ (B
0) about 1 effect in agreement with theory
Is there a problem for B ?
Theory News…..
Next improvements :
(B+)/ (B0) from B factories
But more important (B0
s) and ( B ) from TeVatron …. and B Bc, c
Experiment side:
Theory side:
Improvements of the Lattice QCD calculations
md ms
WORKING
GROUP
IIRadiative and Leptonic B decays
Rare K decays
d, s bd, sb
Vtd ,Vts
B Oscillations
Present
Future
)cos1(21 /
)( 000 tmeP qt
BBBq
qqq
Study of the time dependent behaviour
of the Oscillation B0 -B0
TextBook Plot
BeforeB-Factories
md
LEP/SLD/CDF precisely measured the md frequencymd = 0.498 ± 0.013 ps-1 LEP/SLD/CDF (2.6 %)
B-factories confirmed the value improving the precision by a factor 2md = 0.496 ± 0.007 ps-1 LEP/SLD/CDF/B-factories (1.4%)
The final B-factories precision will be about 1% ( 0.004 ps-1 )
)cos1(21 /
)( 000 tmeP qt
BBBq
qqq
A
Combination of different limits using the amplitude methods
Combination using A and A
ms
ms excluded at 95% CL A + 1.645A < 1
At given msA = 0 no oscillation A = 1 oscillation
Sensitivity same relation with A = 0
1.645A < 1
Measurement of A at each ms
ms > 14.9 ps-1 at 95% CL
Sensitivity at 19.3 ps-1
“Hint of signal”at ms=17.5 ps-1 but with significance at 1.
Expectation inThe Standard Modelms [14.1-21.6] ps-1 at 95% CL
Very important achievement. The ms information has to be included in the CKM Fitsusing the Likelihood Method.( in the past this was a source of differences between the groups performing CKM fits)
WORKING
GROUP
IIICKM Fits Strategies
the angle Vud,Vus
Two subgroups :
1-2/2 A 3(i)
1-2/2 A2
A 3(1--i) -A2 1
u
c
t
d s b
bd, s b
Vtd ,Vts
B Oscillationsd, s
Vtb
c,u
B decays
bVub,Vcb
The CKM MatrixIn the Wolfenstein parameterization 4 parameters : ,A,
bu / bc | Vub \ Vub |2 2 +
md |Vtd|2fBd2 BBd f(mt) 2 +
md \ md |Vtd \ Vtd |2 fBd2 BBd \ fBs
2 BBs 2 +
K f(A,BK..)
Ex : BK = 0.87 ± 0.06 (gaus) ± 0.13 (theo.) Treatment of the inputs
Rfit Bayesian
p.d.f. from convolution (sum in quadrature)
Likelihood
Delta Likelihood
Likelihood obtained summing linearly the two errors
Delta Likelihood
[0.68-1.06] [0.76-0.98]At 68% CL
Where the difference is coming from ?
Difference comes from how the inputs are treated :At present mainly from: F(1), inclusive Vcb, BK
Breakdown of the error is important
The splitting between Gaussian and theoretical error is crucial and somehow arbitrary
Results of the Workshop : theoretical error reduced and origin of the error better defined
K ( Vcb4 * BK)
Differences are small and physics conclusions quantitatively the same
The difference ( which is by the way small ) on the CKM quantities coming from the different methods, is essentially due to the different treatment of the theoretical errors
Using Likelihoodsas obtained from linear sum of Exp.+Theo. errors
Using Likelihoodsas obtained from convolution of Exp. Theo. errors
Both methods use the same likelihood
Differences almost disappears
Another example with sin2 (without K )
[0.14-0.30]
[0.24-0.39]
at 95%CL
= 0.220 ± 0.040 = 0.315 ± 0.038
at 68%CL
Which are the predictions : sin2, , ms
sin2 [0.57-0.81] [43.6-67.3]o at 95%CL
ms [14.1-21.6] ps-1
sin2 = 0.78 ± 0.08 From B J/ K0s
First crucial test done
Winter 2002
1995
1988
Mainly thanks to m
easurements
done at LEP after the end of data taking
What will happen next ?
Proceedings by Summer : Yellow Book + simultaneous publicationin other laboratories (Slac/Tevatron/Cornell..)
We hope with significant improvement from B-factories Next Workshop, late Spring 2003 in UK ( Lake District )
Aim is to have a LHC preparation workshop in year B LHC -2 But may well be need for a further a Workshop before….
B Physics has been intensively studied during last 10 years at LEP/SLD/TeVatron and CLEO and spectacular improvements have been obtained in the last years