Heavy flavour Leptonic and SL. Decays B and D leptonic decays B→cl B→ul D semileptonic decays Present achievements and perspectives 15/06/2007 GDR Physique subatomique et calculs sur réseaux

Physics motivation(s) Rechercher des anomalies dans les transitions entre quarks Etudier l’interaction forte 15/06/2007 GDR Physique subatomique et calculs sur réseaux 2

Experiments (e+e- colliders) LEP CLEO-c Cornell Campus BaBar SLAC FNAL BB threshold DD threshold Belle KEK Japan BESIII IHEP Beijing Superb 15/06/2007 GDR Physique subatomique et calculs sur réseaux 3

GDR Physique subatomique et calculs sur réseaux D leptonic decays At threshold: CLEO-c now ~300pb-1 registered (about half the total) 50 evts D+→μ, 140 evts Ds+→μ / τ 15/06/2007 GDR Physique subatomique et calculs sur réseaux 4

GDR Physique subatomique et calculs sur réseaux D leptonic decays At Upsilon(4S): BaBar, 230 fb-1 (1/4 final sample) e+e-→Ds* D X; Ds*→Ds; Ds+→μ Summary f (D+) = 223173 MeV f(Ds) = 270137 MeV f(Ds) = 28317714 MeV f(Ds)/ f (D+) =1.220.090.03 15/06/2007 GDR Physique subatomique et calculs sur réseaux 5

D leptonic decays,perspectives Statistically limited End of CLEO-c (2008-9?) (f)/f ~5 dominated by statistics BES3 (starting) 20 fb-1 at DD threshold (f)/f ~1.2 12 fb-1 at DsDs* threshold (f)/f ~0.9 Need to run at threshold energy Super-Flavour factory (2012…) 100 fb-1 in a month (f)/f <0.5 15/06/2007 GDR Physique subatomique et calculs sur réseaux 6

B leptonic decays BR(B+→μ) expected at 5 10-7 End of b-factories (2 ab-1) (BR)/BR ~30 SuperB (75 ab-1) (BR)/BR ~4-5 for τ and μ 15/06/2007 GDR Physique subatomique et calculs sur réseaux 7

B →cl, exclusive analyses B→D* l  3 hadronic form factors, use HQET+analyticity constraints →F(1) and 2 (slope) of ISGW FF Results still based on a small fraction of the statistics at B-factories (~80 fb-1 or ~1/10 of final sample) F(1) Vcb = (36.00.6)10-3, (1.7 accuracy) Prob.2~0.005 !! 15/06/2007 GDR Physique subatomique et calculs sur réseaux 8

B →cl, inclusive analyses Vcb or Vub Hadronic parameters: μ2, μG2, D3, SL3 Quark masses: mb, mc Perturbative QCD expansion and 1/mb expansion SL=τ BRSL Moments of lepton energy and hadronic mass system depend on the same hadronic parameters b→c and b→u transitions depend on the same parameters 15/06/2007 GDR Physique subatomique et calculs sur réseaux 9

B →cl, inclusive analyses (moments) 1.7% Can be used for b→ul 15/06/2007 GDR Physique subatomique et calculs sur réseaux 10

B →cl, inclusive analyses caveat? Bd→D(*)l (%) 2.30.30.3 Aleph 2.70.70.2 Delphi 1.50.20.2 Belle 2.80.4 incl.-excl. HFAG What are the « missing » D** states made-off? Is τ3/2 >> τ1/2? Expect D(*) contributions? 15/06/2007 GDR Physique subatomique et calculs sur réseaux 11

Perspectives on B →cl Now: already quite accurate Vcb(excl.) = (39.60.71.8)10-3 Vcb(incl.) = (41.60.7)10-3 With 1/10 of available stat. Lattice error on F(1) End of b-factories Difficult to predict? (systematics, manpower) Much more information exploited in exclusive and inclusive decays (limitation in exclusive from F(1) from lattice?) 15/06/2007 GDR Physique subatomique et calculs sur réseaux 12

GDR Physique subatomique et calculs sur réseaux Vub determination From Morii 15/06/2007 GDR Physique subatomique et calculs sur réseaux 13

B →ul, inclusive analyses Low S/B, Measurements in restricted regions of phase-space Vub=(4.520.19 0.27)10-3 6% accuracy 15/06/2007 GDR Physique subatomique et calculs sur réseaux 14

B →Xl, exclusive analyses Tag using the other B (hadronic or s.l. decay) or untagged analyses, different levels of purity and statistics 15/06/2007 GDR Physique subatomique et calculs sur réseaux 15

B →Xl, exclusive analyses B(B0→l)=(1.390.08)10-4 6% accuracy 15/06/2007 GDR Physique subatomique et calculs sur réseaux 16

GDR Physique subatomique et calculs sur réseaux Perspectives on B→ul Now: Vub(excl.) = (35.01.04.0)10-4 Vub(incl.) = (44.93.3)10-4 With 1/2 of available stat. Some 2 difference Lattice error on F(q2) End of b-factories Difficult to predict? (systematics) Much more information exploited in exclusive and inclusive decays (limitation in exclusive from F(q2) from lattice?) Superb Allows high stat. accuracy on golden channel(s): B→P/Vl 15/06/2007 GDR Physique subatomique et calculs sur réseaux 17

GDR Physique subatomique et calculs sur réseaux D→Xl D  K e n form factor shape measurement CLEO-c and BaBar are entering into a new accuracy area. 15/06/2007 GDR Physique subatomique et calculs sur réseaux 18

D→Kl LQCD pole=0.500.04 f+(0)=0.730.030.07 f+(q2)=0.7270.0070.0050.007 LQCD pole=0.500.04 f+(0)=0.730.030.07 experiment stat mpole(GeV/c2) αpole CLEO-c 281 pb-1 1.97±0.02±0.01 0.21±0.04±0.03 FOCUS 13k evts 1.93±0.05±0.03 0.28±0.08±0.07 Belle 282 fb-1 1.82±0.04±0.03 0.52±0.08±0.06 BaBar 75 fb-1 1.884±0.012±0.016 0.38±0.02±0.03 Not a complete agreement 15/06/2007 GDR Physique subatomique et calculs sur réseaux 19

GDR Physique subatomique et calculs sur réseaux D→l 15/06/2007 GDR Physique subatomique et calculs sur réseaux 20

GDR Physique subatomique et calculs sur réseaux B0-B0 oscillations Dms : already a high precision measurement (~2.3%) CDF 2006 Asymmetry  cos(Dmdt) Dmd = 0.5070.004 ps-1 |Dt| (ps) 10% error 15/06/2007 GDR Physique subatomique et calculs sur réseaux 21

GDR Physique subatomique et calculs sur réseaux The D/B connection? Need for accurate values of fB (oscillations) and f(B→) (Vub) Have already(soon) accurate values for fD and f(D→) Can theory (lattice) provides the connection? fB = F(lattice) fD ? , f(B→) = G(lattice) f(D→)|same p ? Seems possible (Damir ….) Are there people working on these aspects? 15/06/2007 GDR Physique subatomique et calculs sur réseaux 22

GDR Physique subatomique et calculs sur réseaux Conclusions Decay constants and FF of D approaching % accuracy situation can improve to few per mille if SuperC Several values of CKM parameters limited in accuracy by the determination of hadronic parameters Can the D/B connexion improves the situation? Need to better understand LQCD uncertainties and how to include them in global fits Why quoted errors for Vcb and Vub inclusive results seem too optimistic for some theorists? ………. SM tested at ~10% (with 2  “effects”) we need to reach the % level (New physics from LHC can have effects at that level In flavour physics) : need for SuperB and SuperLQCD. 15/06/2007 GDR Physique subatomique et calculs sur réseaux 23