1- 2 /2  1- 2 /2 u c dsb A 3 (1-  -i  ) - A 2 t d, s b b V td,V ts B Oscillations A 3 (  i  ) A 2 1 V tb c,u B decays b V ub,V cb Wolfenstein parametrization 4 parameters :, A,  The CKM matrix 2Theory

Experiments at the Z /  ( 4S ) 3 p B ~ 1 GeV p B ~ 30 GeV Z  bb  (4S)  BB CLEO ALEPH DELPHI OPALBABAR The DELPHI experiment p B ~ 0.3 GeV BELLE ~ 150 M ~ 3.4 M ~ 0.8 M

4 Event Selection Analysed data samples Lifetime probability

5 Event Reconstruction Analysed data samples D mass resolution Decay distances

6 Discriminant variables Analysed data samples ~80%~80% ~80% ~46% Q X < 0Q X =

q 2 measurement 7|V cb | from

q 2 measurement 8|V cb | from

Fit 9  Event by event likelihood: P(q 2 ) P(  m) P(d + )P(d - ) + Constraints on N j (except for combinatorial and D** backgrounds) N signal  dd dq 2 dq2dq2  dNdN |V cb | 2 F 2 (w) K(w)  eff(q 2 )  res(q 2 )  F(w) as function of the f.f.  2, R 1 and R 2.  Fit F(1)|V cb | and  2 meas. 

Results on simulated events 10|V cb | from Generator level Reconstruction level

11|V cb | from Results on individual samples

12|V cb | from Fixing the BR = (0.67 ± 0.08 ± 0.11)%

DELPHI average 13|V cb | from DELPHI average: Results: Increased statistics (   4) New channel (K -  + (  0 )) Improvements in the reconstruction (E b, m D* ) Control on background New observables New measurements

Results on Real Data 14|V cb | from

Systematic uncertainties 15|V cb | from External parameters K -  + X rates: b fragmentation:

Systematic uncertainties 16|V cb | from Detector 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 17|V cb | from Detector performance d ± distributions:

Systematic uncertainties 18|V cb | from Signal and background modelling Signal:

Systematic uncertainties 19|V cb | from Background modelling D* 2 D* 1 D1D1 Model 1Model 2 q 2 sim

Comparison with other measurements 20|V cb | from

21 Systematics |V cb | from

Probability distributions 22D** properties

Probability distributions 23D** properties

RD/MC 24D** properties

Discriminat variables 25D** properties

Discriminat variables 26D** properties

Discriminat variables 27D** properties

Cascade correction factors 28D** properties

Systematics 29D** properties R*

Backgr. mass distribution RD/MC 30D** properties  = 0.5  0.2 i = 3, 5

Non-resonant contribution 31D** properties

32 Non-resonant contribution = 0.42% H.-Y. Cheng et al. PRD48 (‘93) 3204

D  contribution 33D** properties

Efficiencies 34D** properties

Fit  m wrong sign candidates 35D** properties

Fit  m RS cand. for 0.25 < R < D** properties

D s spectroscopy 37D** properties

OPE formalisms 38 1, 2 1, 2  ,  G  1,  2,  i (i=1,4)  D,  LS    Energy of light quarks and gluons (related m b, m c with m b, m c ) 1   1 (   )  Kinetic energy of the b quark inside the meson 2  G 2 (  G ) = chromo-magnetic coupling  (M B* -M B ) |V cb | from inclusive decays Pole mass expansion Kinetic mass (  =1GeV) Kinetic mass (  =1GeV) Can be measured

Spectral moments 39|V cb | from inclusive decays Inclusive observables  O  CLEO CONF PRL ’01 PRL ’01 PDG2002 |Vcb|=(40.8  0.5  2.5)  |Vcb|=(40.4  0.5  0.5  0.8)  CLEO PDG2000  = (0.35 ±0.07±0.10) GeV 1 =( ±0.071±0.078) GeV 2 Photon and lepton energy (E , E l ), Mass hadronic distribution (M x ),... sb  q2q2  cb Expressed in terms of the same theoretical parameters

Moments of the D** distribution 40|V cb | from inclusive decays Inclusive b semileptonic LEP  78% B d, B -  22% B s,  b  22% D  50% D*  28% D** Exclusive processes Moments of the total hadronic mass distribution in b  c - Inclusive decay width determination Study of D** properties Known

Systematics on moments 41|V cb | from inclusive decays

Combining information on moments Moments Moments of the lepton energy spectrum by DELPHI (DELPHI CONF-604) Combined fit to the 3 first moments of hadronic and leptonic moments Two formalisms m q pole m q kin (q) Included  s and (1/m b ) 3 corrections Constraints from external results  2 fit to 6 moments  s = 0.22 ±

Pole mass formalism 43Moments Fixing Constraints from and  = 0.35 ± 0.07 ± 0.10 GeV 1 = ± ± GeV 2  = 0.53 ± 0.09 GeV 1 = ± 0.09 GeV 2 BABAR CLEO

Comparison with other measurements 44Moments |V cb | (inclusive) Control on non-perturbative corrections up to O(1/m b ) 3 Well defined scheme Remaining perturbative corrections ~ 1 % Error of |V cb | ~ 2%

Updated results |V cb | from moments45 Using the numerical expression of the  sl advised by N. Uraltsev : New moment expressions by P. Gambino :

|V cb | from moments46 BPS limit Allows an accurate extraction of N. Uraltsev (Bogolmo’nyi-Prasad-Sommerfeld)

47Moments The b quark mass Ph.D. M.J. Costa Ph.D. P. Tortosa This result

Summary and conclusions 48Summary and conclusions |V cb | from Competitive with LEP, CLEO and b-factories Errors of |V cb | dominated by the theory Improves the previous result from DELPHI Large dispersion between results from several experiments  Need for more measurements Measurement of b s.l. decays to higher mass states Need measurements of form factors, production rates, BR’s…

Summary and conclusions 49Summary and conclusions D** properties Measurement of the production rates of D** Study of the D** mass distribution First determination of D 1 * properties in B s.l. decays Compatible results of D 0 * properties Measurement of the 3 first moments of the hadronic mass distribution First measurements at low p First measurements at low p Compatible result with CLEO and BABAR  check OPE consistency Increased stat., improved syst. D**  D  production limits

|V cb | from the inclusive decay width Accurate determination of |V cb | Development of the kinetic mass scheme Combined fit to 6 DELPHI moments Quark masses determination Proximity to the BPS limit Control of non-perturbative parameters 50Summary and conclusions