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A. Oyanguren (B A B AR Collaboration) LAL – Orsay (Marie Curie EIF)

A. Oyanguren (B A B AR Collaboration) LAL – Orsay (Marie Curie EIF). 3/11/05 - Physikalisches Institut, Universität Bonn. Outline.  The CKM matrix.  Semileptonic decays of b quarks.  Exclusive |V cb |.  Inclusive |V cb |.  Moment analysis.  D** states.

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A. Oyanguren (B A B AR Collaboration) LAL – Orsay (Marie Curie EIF)

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  1. A. Oyanguren (BABAR Collaboration) LAL – Orsay (Marie Curie EIF) 3/11/05 - Physikalisches Institut, Universität Bonn

  2. Outline The CKM matrix Semileptonic decays ofbquarks Exclusive |Vcb| Inclusive |Vcb| Moment analysis  D** states Semileptonic decays of c quarks  Calibrating Lattice-QCD Summary 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 2

  3. The CKM matrix Weak interactions of quarks in the SM: The CKM matrix: VudVusVub Vcd VcsVcb VtdVtsVtb VCKM= mq + Vqq’ 10 fundamental parameters of the Standard Model 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 3

  4. The goal: Understand the SM picture The CKM matrix In the SM: VCKMunitary 4 free parameters Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb VCKM=  Wolfenstein Parameterization l = |Vus|= 0.2227  0.0017 l 1-l2/2+O(l4) Al3(r-ih) Al2 -l+O(l5) VCKM ~ 1-l2/2+O(l4) Al3(1-r-ih)+O(l5) -Al2+O(l4) 1+O(l4) to be able to find New Physics signatures 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 4

  5. The unitary clock Vcb and Vub have akey role  determinedfrom tree level processes The Unitarity Triangle (UT) * Vud Vcd Vtd Vus Vcs Vts Vub Vcb Vtb Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb VudVub* + VcdVcb* + VtdVtb* =0 = (r,)  a g b (1,0) (0,0) The idea: Overconstrain the UT Other approaches: http://www.slac.stanford.edu/xorg/ckmfitter 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 5

  6. Instead of : Vcb We deal with : Vcb The problem The problem: quarks are confined inside hadrons... 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 6

  7. l nl q2 x X’ Vxx’ The theoretical tools sl = |Vxx’|2f (theory) Exclusive processes: Inclusive processes: 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 7

  8. Heavy Quark Effective Theory For heavy quarks  expansions in 1/mQ  flavour and spin symmetries relations between form factors QCD computations form factor calculations Lattice-QCD Difficult to put quarks of different mass in the lattice Need calibration The theoretical tools Exclusive processes: Vcd Parameterized by form factors 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 8

  9. Measurement of moments: Some inclusive observablesO  depend on the same parameters HbHc (For instance: ) : the lepton energy, the mass distribution of HC Same parameters for bcand bu transitions The theoretical tools Operator Product Expansion Inclusive processes: for heavy quarks = x Vcb f( parameters related with b quark properties inside the hadron )  kinetic energy, spin... 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 9

  10. Measuring Vcb 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 10

  11. (4S) BB Z  bb The experiments BABAR PB~ 30GeV BELLE PB~ 1GeV DELPHI CLEO (III) CLEO OPAL ALEPH PB~ 0.3GeV 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 11

  12. Normalized by HQET (mQ  ) at q2max FD*(1)=1 (1/ mQ )n and QCD corrections  FD*(1)= 0.91  0.04 Exclusive measurement of |Vcb| Known function Form factor of the B D* transition The shape parameterized with a form factor slope  2 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 12

  13. Exclusive measurement of |Vcb| D*+ - l- candidates Eur. Phys. J. C33 (2004) 213 B  D*l- D0 soft m= m(D0) -m(D0) ~ m(soft) D0  K-+ D0  K- + - + D0  K-+(0) 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 13

  14. Exclusive measurement of |Vcb| World average |Vcb|=0.0413  0.0010  0.0020 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 14

  15. sl incl = B(BXcln)/B = |Vcb|2f() d|Vcb| < 1% |Vcb|  Need the same accuracy in Getting these parameters from other observables: Ex: Studying the Xchadronic mass distribution f ( ) What is Xc? Inclusive measurement of |Vcb| B = 1.568  0.009 ps B(BXcln) = (10.70 0.14)% 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 15

  16. HQET: D* 52% D 21% ? D**  27% Ground states Broad states Narrow states The hadronic system Xc 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 16

  17. D** mass distribution Exclusive reconstruction of Right sign Wrong sign ALEPH [ZP C73 (97) 601] D(*)pp contributions Right sign Found < 0.22% Wrong sign 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 17

  18. BNR= (0.23  0.35  0.44)% sNR= (5.0  7.0) (GeV/c2)-1 D** mass distribution DELPHI fit superimposed to CDF data considering B(D1,D*1 Dpp =(2015)% [PRD 71 (05) 051103] CERN-EP-PH-2005-015 Narrow states BD1= (0.56 0.10)% (constrained) BD*2= (0.30 0.08)% Broad states BD*1= (1.24  0.25  0.27)% mD*1=2445  34  10 MeV D*1= 234  74  25 MeV BD*0= (0.42  0.33 0.22)% D*0= 260  130  130 MeV (CDF normalized to the # DELPHI entries) 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 18

  19. 2 3 rLS G |Vcb|from Moments Moments of the hadronic mass distribution + Moments of the lepton energy spectrum Fixing ( ~ MB*-MB ) , and using constraints on mb and mc 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 19

  20. OPE parameters from DELPHI Theo. uncertainty LEPB(BXcln) |Vcb|from Moments Phys.Lett. B556 (2003) 41 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 20

  21. |Vcb|from Moments The big success of OPE (hep-ph/0507253) 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 21

  22. Something puzzeling Theoretical predictions(OPE values, sum rules, lattice QCD) B(B narrow(jq=3/2)ln) >> B(B broad (jq=1/2)ln) B(B0Xcln) - B(B0Dln) - B(B0D*ln) = (2.9  0.3)% B(B0 D**ln) = (2.7  0.7  0.2)% With narrow states only accounting for (0.86  0.13) % B(B narrowln) < B(B broad ln) Measured broad component not (only) jq=1/2? ( 0’, L>1 states?) Large 1/mc contributions in the theoretical predictions? 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 22

  23. Decays of c quarks 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 23

  24. Computations need to be confronted with experimental results Lattice-QCD d QCD computations in a space-time lattice parameters: s and quark masses a matrix elements: decay constants, form factors... Current Lattice-computers ~ teraflop = 1012 operations/sec. Difficult to put together quarks of very different mass  approximations Difficult to include dynamical quark-pairs  unquenched Impressive accurate results Ex: new result of fB = 216  22 MeV (HPQCD) affecting md  |Vtd| accuracy from 16% to 11% 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 24

  25. Using exclusive semileptonic decays of charm hadrons to measure form factors and validate Lattice QCD results Semileptonic decays of c quarks In the charm sector: Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb Vcd, VcsConstrained from measurements of the two first rows Vcd Parameterized by form factors 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 25

  26. Semileptonic decays of c quarks D K l n andD pl n decays Phys. Lett. B317 (1993) 647  High accuracy needed to measure the q2- dependence 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 26

  27. Semileptonic decays of c quarks Lattice QCD form factors (D K, D p) Fermilab + MILC, hep-ph/0408306  BES, Phys. Lett. B597 (04) 39 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 27

  28. Semileptonic decays of c quarks Charm Semileptonic Decays: Calibrate Lattice QCD results Improve results on B decays fp, fB, fB* , gB*Bp |Vub|measurement: 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 28

  29. Experimental setups (4S)@ B factories Y(3770) @ charm factories BELLE CLEO-c BES-III BABAR DD BB 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 29

  30. Experimental setups Some advantages and disavantages (4S)  cc  DD Y(3770) Large cc (~1.3 nb) Very large DD (~6 nb) Low multiplicity Very large statistics Small background Vertex separation Fragmentation (cD* = 26%) Well known En Background Still few data 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 30

  31. Experimental techniques At the Y(3770) CLEO-c Unique kinematics: pp(GeV) DE=Ebeam-ED No PID DU=Emiss-pmiss s.l. channel D  p e n CLEO-c hep-ex/0408077 D  K e n Preliminary D  p e n DU=Emiss-pmiss (GeV) Tagged D CLEO-c Events/5 Mev 10183  112 Events/1 Mev 60 pb-1 Expected resolution on q2 ~ 0.03 GeV2 MD (GeV) DU=Emiss-pmiss (GeV) 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 31

  32. Experimental techniques At the (4S) bb/cc separation  event shape variables BB Continuum events: e+e- cc cc from all particles in the event En estimation  D*+ D0 + s ~ 0.35 GeV q2 = (pl+ pn)2 =(pD – pK )2 50904 evts Events/1.6 Mev data Resolution on q2 found ~ 0.05-0.25 GeV2 Events/2.7 Mev 19.5 fb-1 D  K e n Background contribution  Dm (GeV) Dm (GeV) 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 32

  33. Experimental techniques Comparisons: 2006 20 fb-1 300 fb-1 6.7 fb-1 3 fb-1 ? 60 pb-1 10K 6K 1800 90K 30K 450K 0.9K 0.3K 175 9K 3K 45K * D  K form factor by FOCUSwith 6K events *Challenge: background suppression BaBar 5 times more stat. only with 20 fb-1 (Run1) 0.4 0.22 0.03 0.05-0.25 And good q2 resolution Phys.Lett. B607 (2005) 233-242 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 33

  34. Summary |Vcb| and |Vub| are key elements of the CKM matrix |Vcb|accuracy is at the 1.2% level (world average) by using inclusive decays and OPE Charm Semileptonic Decays provide a way to calibrate Lattice-QCD computations  Improve|Vub| 3/11/05 - Physikalisches Institut, Universität Bonn A. Oyanguren 34

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