Download presentation
Presentation is loading. Please wait.
1
A big success with more than 200 participants
2
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 and future measurements : - in a short timescale (B-Factories/TeVatron II) - in a longer timescale (bridging today LHC)
3
Structure of the Workshop
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
4
The CKM Matrix d s b u c t -Al2 4 parameters : l ,A, r, h 1-l2/2 l
In the Wolfenstein parameterization 4 parameters : l ,A, r, h The CKM Matrix d s b u 1-l2/2 l A l3(r-ih) b c,u Vub,Vcb c -l 1-l2/2 Al2 B decays t A l3(1-r-ih) -Al2 1 Vtb b d, s Vtd ,Vts B Oscillations
6
Theoretical assumptions Theoretical uncertainties
Measurements Measurements Theory UT parameters Analysis Methods Analysis Systematic To be continued at B-Factories and TeVatron Theoretical assumptions Theoretical uncertainties Possible measurements Error Meaning (discussion) Statistical Methods to extract UT parameters
7
WORKING GROUP I b c,u Vub,Vcb B decays Lifetimes Vcb Vub
8
Inclusive Determination of Vcb
BR sl t b Average by LEP Working Groups
9
mb m2p Vcb = 0.0415 ( 1 - 0.012 m2p - 0.010 mb + 0.006 as + 0.007 r
Determination of Vcb limited by theoretical uncertainties ….. The expression of Vcb in the low scale running HQ masses formalism (as an example)* Vcb = ( m2p mb as r mb (l1 Fermi movement inside the hadron) ( also named L) m2p Can these parameters be determined experimentally ? * In “Upsilon expansion” formalism : Vcb = ( l mb pert)
10
From CLEO measurements
12
Other experiments should perform this analysis …….
13
Vcb(inclusive)= ( 40.7 ± 0.7 ± 0.8 ) 10-3
Part of theoretical error on Vcb becomes experimental from the determination of m2p and mb Value agreed at the end of the Workshop Vcb(inclusive)= ( ± 0.7 ± 0.8 ) 10-3 It was ± 2.0 and of theo. origin !
14
Exclusive Determination of Vcb
G(w) contains kinematics factors and is known (also r1 and r2) F(w) is the form factor describing the B D* transition At zero recoil (w=1), as MQ F(1) 1 Strategy : Measure dG/dw and extrapolate to w=1 to extract F(1) Vcb
15
F(1) |Vcb|2 Syst. dominated by the knowledge of the D** (for LEP) r2
16
F(1) 3 determinations At the Workshop agreement on F(1) = 0.91±0.04 (Gauss.)
17
What’s next to improve Vcb
Experimental side: More and new moment analyses B-factories can perform both exclusive and inclusive analyses Form factors measurements in BD*ln Theory side : More work on the theory for the m2p ,mb extraction Unquenched F(1) calculations Studies of eventual correlation between inclusive and excluive determinations
18
Vcb = (41.8 ± 1.0 ) 10-3 Combing the inclusive and the exclusive
measurements : Vcb = (41.8 ± 1.0 ) 10-3
19
Vub Inclusive determination of Vub from LEP b c b u
Challenge measurement from LEP Using several discriminant variables to distinguish between the transitions : b c b u B Xu l n
20
Results from all the LEP experiments
22
At the Workshop we agreed on
New determination At the Workshop we agreed on Vub(inclusive) = (4.09 ± 0.46 ± 0.36) 10-3
23
B ® p(r) l n Exclusive determination of Vub
Vub = (3.68 ± (syst.))10-3 (in ISGW2 Model) - 0.37 Babar Vub = (3.68 ± (syst.)± 0.55(theo.))10-3 CLEO - 0.29 Important theoretical uncertainties from different models NOW, Lattice QCD calculations start to be precise
24
What’s next to improve Vub
Experimental side: B-factories can perform inclusive/end-point/exclusive analyses Correspondence between Dpln and B pln 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
25
Lifetimes All lifetimes of weakly decaying B hadrons
have been precisely measured Very important test of the B decay dynamics
26
Averages from LEP/SLD/Tevatron (+ B-Factories)
t(B0d) = ± ps ( 1.0%) t(B+) = ± ps ( 0.9%) t(B0s) = ± ps ( 3.9%) t(LB) = ± ps ( 4.2%) The hierarchy was correctly predicted ! t(B+)/ t(B0) about 5s effect in agreement with theory t(B0s)/ t(B0) about 1s effect in agreement with theory Is there a problem for LB ?
27
Theory News…..
28
t(B0s) and t( LB ) from TeVatron …. and B Bc, c
Next improvements : Experiment side: t(B+)/ t(B0) from B factories But more important t(B0s) and t( LB ) from TeVatron …. and B Bc, c Theory side: Improvements of the Lattice QCD calculations
29
II WORKING GROUP Dmd Dms B Oscillations d, s b Vtd ,Vts
Radiative and Leptonic B decays Rare K decays
30
Present Future
31
Study of the time dependent behaviour
of the Oscillation B0 -B0 TextBook Plot
32
Dmd LEP/SLD/CDF precisely measured the Dmd frequency
Dmd = ± ps-1 LEP/SLD/CDF (2.6 %) B-factories confirmed the value improving the precision by a factor 2 Dmd = ± ps-1 LEP/SLD/CDF/B-factories (1.4%) Before B-Factories The final B-factories precision will be about 1% ( ps-1 )
33
Dms Dms excluded at 95% CL Measurement of A at each Dms At given Dms
Combination of different limits using the amplitude methods Measurement of A at each Dms Combination using A and sA Dms excluded at 95% CL A sA < 1 At given Dms A = 0 no oscillation A = 1 oscillation Sensitivity same relation with A = 0 1.645sA < 1
34
“Hint of signal” at Dms=17.5 ps-1 but with significance at 1.7s Expectation in The Standard Model Dms > 14.9 ps-1 at 95% CL Dms [ ] ps-1 at 95% CL Sensitivity at 19.3 ps-1
39
Very important achievement.
The Dms information has to be included in the CKM Fits using the Likelihood Method. ( in the past this was a source of differences between the groups performing CKM fits)
40
WORKING GROUP III CKM Fits Strategies the angle g Vud,Vus
Two subgroups :
41
The CKM Matrix d s b u c t -Al2 4 parameters : l ,A, r, h 1-l2/2 l
In the Wolfenstein parameterization 4 parameters : l ,A, r, h The CKM Matrix d s b u 1-l2/2 l A l3(r-ih) b c,u Vub,Vcb c -l 1-l2/2 Al2 B decays t A l3(1-r-ih) -Al2 1 Vtb b d, s Vtd ,Vts B Oscillations
42
bu / bc | Vub \ Vub |2 r2 + h2 Dmd |Vtd|2fBd2 BBd f(mt) (1-r)2 + h2 Dmd \ Dmd |Vtd \ Vtd |2 fBd2 BBd \ fBs2 BBs eK f(A,h,r,BK..) h(1-r)
44
Rfit Bayesian Treatment of the inputs
Ex : BK = 0.87 ± 0.06 (gaus) ± 0.13 (theo.) Rfit Bayesian p.d.f. from convolution (sum in quadrature) Likelihood obtained summing linearly the two errors Likelihood Delta Likelihood Delta Likelihood [ ] [ ] At 68% CL
47
Where the difference is coming from ?
eK ( Vcb4 * BK) 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
48
Differences are small and physics conclusions
quantitatively the same
49
Both methods use the same likelihood
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 Likelihoods as obtained from linear sum of Exp.+Theo. errors Both methods use the same likelihood Using Likelihoods as obtained from convolution of Exp. Theo. errors Differences almost disappears
50
Another example with sin2b
(without eK )
51
r = 0.220 ± 0.040 h = 0.315 ± 0.038 at 68%CL r [0.14-0.30] at 95%CL
52
Which are the predictions : sin2b, g, Dms
g [ ]o at 95%CL Dms [ ] ps-1 sin2b = 0.78 ± 0.08 From B J/y K0s First crucial test done
53
Mainly thanks to measurements
1988 1995 Mainly thanks to measurements done at LEP after the end of data taking Winter 2002
54
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 What will happen next ? Proceedings by Summer : Yellow Book + simultaneous publication in other laboratories (Slac/Tevatron/Cornell..) Next Workshop, late Spring 2003 in UK ( Lake District ) We hope with significant improvement from B-factories Aim is to have a LHC preparation workshop in year B LHC -2 But may well be need for a further a Workshop before….
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.