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The CKM matrix u d s b 1-l2/2 l A l3(r-ih) b c,u Vub,Vcb c -l 1-l2/2 Al2 t A l3(1-r-ih) -Al2 1 B decays Vtb Vtd ,Vts B Oscillations b d, s Theory d, s b Wolfenstein parametrization 4 parameters : l ,A, r, h 2 Experiments at the Z / (4S) ~ 150 M BABAR (4S) BB pB ~ 30 GeV BELLE DELPHI pB ~ 1 GeV OPAL CLEO ALEPH ~ 3.4 M pB ~ 0.3 GeV The DELPHI experiment Z bb ~ 0.8 M 3 Event Selection Lifetime probability Analysed data samples 4 Event Reconstruction Decay distances D mass resolution Analysed data samples 5 Discriminant variables ~80% ~80% ~80% ~46% QX< 0 Analysed data samples 2 3 QX= 0 1 3 6 q2 measurement |Vcb| from 7 q2 measurement |Vcb| from 8 Fit Event by event likelihood: Nsignal d dq2 dq2 dN |Vcb|2 F2(w) K(w) eff(q2) res(q2) dq2 meas. + Constraints on Nj (except for combinatorial and D** backgrounds) P(q2) |Vcb| from P(m) F(w) as function of the f.f. r2, R1 and R2. Fit F(1)|Vcb| and r2 P(d+) P(d-) 9 Results on simulated events Generator level |Vcb| from Reconstruction level 10 Results on individual samples |Vcb| from 11 Results on individual samples Fixing the BR |Vcb| from = (0.67 ± 0.08 ± 0.11)% 12 DELPHI average Increased statistics ( 4) Results: New channel (K- +(0)) Improvements in the reconstruction (Eb, mD*) Control on background New observables New measurements DELPHI average: |Vcb| from 13 Results on Real Data |Vcb| from 14 Systematic uncertainties External parameters K-+X rates: |Vcb| from b fragmentation: 15 Systematic uncertainties Detector performance Resolution function: Syst. due to the parameterization: F(1)|Vcb| r2 Including/excluding K-+ (0) |Vcb| from F(1)|Vcb| r2 2.0% 5% 1.0% 3.5% 16 Systematic uncertainties Detector performance d± distributions: |Vcb| from 17 Systematic uncertainties Signal and background modelling Signal: |Vcb| from 18 Systematic uncertainties Background modelling Model 1 Model 2 D*1 D*2 D1 q2sim |Vcb| from q2sim 19 Comparison with other measurements |Vcb| from 20 Systematics |Vcb| from 21 Probability distributions D** properties 22 Probability distributions D** properties 23 RD/MC D** properties 24 Discriminat variables D** properties 25 Discriminat variables D** properties 26 Discriminat variables D** properties 27 Cascade correction factors D** properties 28 Systematics R* D** properties 29 Backgr. mass distribution RD/MC = 0.5 0.2 i = 3, 5 D** properties 30 Non-resonant contribution D** properties 31 Non-resonant contribution = 0.42% H.-Y. Cheng et al. PRD48 (‘93) 3204 D** properties 32 D contribution D** properties 33 Efficiencies D** properties 34 Fit m wrong sign candidates D** properties 35 Fit m RS cand. for 0.25 < R < 0.70 D** properties 36 Ds spectroscopy D** properties 37 OPE formalisms Pole mass expansion Kinetic mass (=1GeV) l 1, l 2 2, 2G Can be measured |Vcb| from inclusive decays r1, r2, i (i=1,4) 3 rD3 , rLS Energy of light quarks and gluons (related with mb, mc ) l1 (2 ) Kinetic energy of the b quark inside the meson l2 (2G) = chromo-magnetic coupling (MB*-MB) 38 Spectral moments Expressed in terms of the same theoretical parameters PRL 87 251807 ’01 PRL 87 251808 ’01 Inclusive observables O b Photon and lepton energy (E, El), Mass hadronic distribution (Mx), ... s l CLEO nl q2 CLEO CONF 98-21 b c = (0.35 ±0.07±0.10) GeV l1=(-0.236 ±0.071±0.078) GeV2 |Vcb| from inclusive decays PDG2000 |Vcb|=(40.8 0.5 2.5) 10-3 PDG2002 |Vcb|=(40.4 0.5 0.5 0.8) 10-3 39 Moments of the D** distribution Inclusive b semileptonic decays Exclusive processes 22% D Known 50% D* Study of D** properties 28% D** @ LEP 78% Bd , B 22% Bs , b Moments of the total hadronic mass distribution in bc l- nl Inclusive decay width determination |Vcb| from inclusive decays 40 Systematics on moments |Vcb| from inclusive decays 41 Combining information on moments Moments of the lepton energy spectrum by DELPHI (DELPHI 2002-070-CONF-604) 2 fit to 6 moments Two formalisms Combined fit to the 3 first moments of hadronic and leptonic moments mqpole mqkin (q) Constraints from external results Included s and (1/mb)3 corrections s = 0.22 ± 0.01 Moments 42 Pole mass formalism Fixing Constraints from and BABAR = 0.53 ± 0.09 GeV l1 = - 0.36 ± 0.09 GeV2 CLEO = 0.35 ± 0.07 ± 0.10 GeV l1 = - 0.238 ± 0.071 ± 0.078 GeV2 Moments 43 Comparison with other measurements Well defined scheme Control on non-perturbative 3 corrections up to O(1/mb) Remaining perturbative corrections ~ 1 % Error of |Vcb| ~ 2% |Vcb| (inclusive) Moments 44 Updated results New moment expressions by P. Gambino : Using the numerical expression of the sl advised by N. Uraltsev : |Vcb| from moments 45 BPS limit N. Uraltsev Allows an accurate extraction of (Bogolmo’nyi-Prasad-Sommerfeld) |Vcb| from moments 46 The b quark mass Ph.D. M.J. Costa Ph.D. P. Tortosa This result Moments 47 Summary and conclusions |Vcb| from Improves the previous result from DELPHI Competitive with LEP, CLEO and b-factories Measurement of b s.l. decays to higher mass states Large dispersion between results from several experiments Need for more measurements Errors of |Vcb| dominated by the theory Need measurements of form factors, production rates, BR’s… Summary and conclusions 48 Summary and conclusions D** properties Measurement of the production rates of D** Increased stat., improved syst. D** D production limits Study of the D** mass distribution First determination of D1* properties in B s.l. decays Compatible results of D0* properties Measurement of the 3 first moments of the hadronic mass distribution First measurements at low pl Compatible result with CLEO and BABAR check OPE consistency Summary and conclusions 49 Summary and conclusions |Vcb| from the inclusive decay width Development of the kinetic mass scheme Combined fit to 6 DELPHI moments Quark masses determination Control of non-perturbative parameters Proximity to the BPS limit Accurate determination of |Vcb| Summary and conclusions 50