Study of B  D S ( * )  D*  *   and D ( * ) (4  )   at CLEO Jianchun Wang Syracuse University Representing The CLEO Collaboration DPF 2000 Aug , 2000 Columbus, Ohio

DPF 2000Jianchun (JC) Wang2 Introduction  Test theoretical understanding of hadronic B decays (Factorization, HQET, Hadronic Matrix Element towards CKM parameters, etc)  Known B decay channels:  Semileptonic modes  30 %  Hadronic B decay modes  12 % (J/  K ( * ), D S ( * ) D ( * ), D ( * ) (n  )  )  Many modes need to be identified  Average # of charge particles in hadronic B decays (  5.8)  Large fraction of B decays to higher multiplicity final states

DPF 2000Jianchun (JC) Wang3 Partial Reconstruction of B  D S  D*   Features of the decay: D S D* back-to-back,  follow D* direction  Full reconstruction of D S  (D S   ,  K  K  ) and    8 unknown, 8 constraint  2 solutions (quadratic ambiguity)  Parameters used in the fit ( independent on the choice ):  : angle between -p Ds and p   0 : lower kinematic limit of   p Ds : magnitude of D S momentum   s : decay angle of slow  in D* frame  DSDS  D*   D B° DSDS D*   DD

DPF 2000Jianchun (JC) Wang4 Distribution of cos  0  cos   Signal: D S ( * )  D* , D S ( * )  D** , D S ( * )  D**  (sharp peak, not distinguished)  Background:BB MC, continuum (constraint from off-resonance data)  Select candidates at peak, number of background fixed for later study  D S ( * )  D* ( * ) :  24.0 BB background:  5.2 continuum: 74.8 cos  0 - cos 

DPF 2000Jianchun (JC) Wang5 Separation of Signals  Fit in two-dimensional space: p Ds and cos    Total 4 parameters in the 2-D fit:  # of D S  D*  (D*  is longitudinally polarized)  # of D S *  D*    L /   # of D S  *  D** (mixture of 12 modes) D S  D*  D S *  D*   D S ( * )  D**  D S ( * )  D** 

DPF 2000Jianchun (JC) Wang6 Projection of 2-D Fit  2 = for ndof=130  4, CL=84.1% D S momentum (GeV) cos   D S ( * ) D** ( 81.6  23.4 )

DPF 2000Jianchun (JC) Wang7 2-D fit without D S ( * )  D** D S momentum (GeV) cos    2 = for ndof =130  3

DPF 2000Jianchun (JC) Wang8 Results from 2D Fit  Fitted yield:  # of D S  D*  : 92.7  14.3  9.3  # of D S *  D*  :  30.4  20.3  # of D S ( * )  D**: 81.6  23.3  14.8  Branching fractions:  B (B°  D S  D*  ) = ( 1.10  0.18  0.11  0.28 ) %  B (B°  D S *  D*  ) = ( 1.82  0.37  0.25  0.46 ) %  B (B   D S ( * )  D**°) = ( 2.73  0.78  0.51  0.68 ) %  D S *  D*  :  L /  = ( 50.6  13.9  3.6 ) %, consistent with factorization prediction of 54% Uncertainty on B (D S  )

DPF 2000Jianchun (JC) Wang9 Full Reconstruction of B  D* +  +      B°  D* +  +      °, D* +  D°  + (D°  K   +, K   +  °, K   +  +   ) Similar spectra observed in D*°(4  )  358  29 E B sidebands signal Fit B yield in each M  bin

DPF 2000Jianchun (JC) Wang10 The  +    Mass Distribution  What are the decay mechanisms for the (4  )  final state ?  Examine the      ° mass spectrum (2 combinations/event). All 3 D° decay modes summed Enlarged & Dalitz plot exterior removed M  (GeV) 

DPF 2000Jianchun (JC) Wang11 The   Mass Distribution  Possible resonance ( temporarily called A )  Simple BW fit: M=1419  33 MeV,  =382  44 MeV D    D    only D o  K   + All 3 D o decays used

DPF 2000Jianchun (JC) Wang12 D  (  )  Angular Distributions  For a spin-0 A, the D* &  would be fully polarized  Spin 0   2 /dof = 3.5 (cos  D* ), 22 (cos   )  Ruled out  Best fit   L /  = 0.63  0.09 (D  ), 0.10  0.09 (  ) Spin-0 expectation

DPF 2000Jianchun (JC) Wang13 The D    Final State  Signal: |  E|<2  (18MeV) Sideband: 3  <|  E|<7   No signal in  sidebands D    (D +  K      ) D   (D o  K   + ) 88   18 E B sidebands Signal

DPF 2000Jianchun (JC) Wang14 The   Mass Distribution Breit-Wigner: Mass = 1415  43  =419  110 MeV  D   and D    modes combined (179 events)  Consistent with D*  result  Combine D*  and D  fit results: mass = 1418  26  19 MeV  = 388  41  32 MeV

DPF 2000Jianchun (JC) Wang15 The Angular Distributions in B  D A    A                between  in A frame & A boost direction  between normal of  decay plane &  boost  between  &  decay planes  Small efficiency corrections applied  For 1 + and 2 , the longitudinal ratio (  L /  ) floats  1 - preferred,  2 /dof (1 - ) = 1.7, (2 + ) = 3.2

DPF 2000Jianchun (JC) Wang16 Identifying the A  with the   Variety of resonances in between 1-2 GeV, which are poorly studied due to limited statistics or wide width  Clegg & Donnachie: (  (   e  e     ,         ) find two 1  states with (M,  ) = (1463  25, 311  62) MeV & (1730  30, 400  100) MeV, only the lighter one decays to , mixed with non-qq states  Godfrey & Isgur: Predict first radial excited  at 1450 MeV,  =320 MeV, B (     )=39%

DPF 2000Jianchun (JC) Wang17 Evidence for  from  Decay          ’’ Difficult to ascertain the Mass and Width CLEO  signal  sidebands

DPF 2000Jianchun (JC) Wang18 Summary & Discussion of Rates   dominates the   final state   B  D    ) /  B  D    ) = 1.04  0.21  0.06  B   D    ) /  B   D   ) = 1.10  0.31  0.06  B  D    ) /  B  D   ) = 1.06  0.17  0.04 Consistent with Heavy Quark Symmetry prediction ( ratio = 1 )  With B (     )=39%,  (B  D (*)   ) ~  B  D (*)   )

DPF 2000Jianchun (JC) Wang19 Factorization Test  Factorization:  L /  (B  D  + h  ) =  L /  (B  D  + l  )| q 2 =m h 2  Excellent agreement between measurements and predictions 63  9   50.6  13.9  3.6 D S *  87.8  5.3    L /  D* + +

DPF 2000Jianchun (JC) Wang20 Model-dependent Decay Constant of   (B  D  + h  ) / d  /dq 2 (B  D  + l  )| q 2 =m h 2 = 6  2 c 1 2 f h 2 |V ud | 2, c 1 =1.1±0.1  Measurement: f  2 B (     ) = ± GeV 2  Godfrey & Isgur predict: B (     ) = 39%  Our measurement  f  = 167 ± 23MeV ( f   220 MeV )

DPF 2000Jianchun (JC) Wang21 Summary  Branching fraction of B  D S ( * ) D* ( * ) measured  Large branching rate of B  D*        D*    and D    modes found  For first time,  observed in B decays (hep-ex/ )  Coupling large, may be similar to   Relatively clean place to establish  mass and width, we find M = 1418±26±19 MeV,  = 388±44±32 MeV   L  ( B  D*h  ) for h  = , and D S *  consistent with factorization predictions   (B  D*   ) /  (B  D   ) satisfy HQET

DPF 2000Jianchun (JC) Wang22 Distribution of cos  0 - cos 

DPF 2000Jianchun (JC) Wang23 Distribution of D s momentum

DPF 2000Jianchun (JC) Wang24 Distribution of cos  