Analysis work by: Marina Artuso Sheldon Stone Jianchun Wang CBX note available: /homes/cleo/sls/dompi.ps Study of B  D   Jianchun Wang 05/12/00

Jianchun (JC) Wang2 Introduction What we have for B  D  (4  )  (3/14 PTA) B  D         ( 1.72  0.14  0.24, 1.80  0.24  0.25 )% D    ( 0.29  0.03  0.04, 0.45  0.10  0.07 )% Possible   resonance(A) at 1419  33,  =382  44 MeV Spin 0 is ruled out Why B  D   ( D o  K   , D   K      ) First observation, branch ratio is already interesting Spin-0 D  easier to identify A

05/12/00Jianchun (JC) Wang3 Selection Criteria Track: ( slow π only first two) TNG approval Good primary track Impact point (0.005,0.03 for p>0.25, 0.01,0.05 for p<0.25) 3  dE/dX consistence for p<0.9 Photon: | cos  | < E9/E25 Not fragment Angcrt > 20  °: (Mass constraint) Multi-bump cut Mass cut: –3.0  to 2.5   : Mass cut: ± 2  (20MeV) Dalitz selection: R<0.7 D: Mass cut: ± 2.5  Momentum dependent  Event: R 2 < 0.3 B: (beam energy constraint) | cos  B | < 0.5  B 2 (  M D,  M ,  M  ) signal: |  E B | < 2 , |  M B | < 2  M sideband: < M B < E sideband: 7  < |  E B | < 3 

05/12/00Jianchun (JC) Wang4 The  E B  M B Distribution D    D  

05/12/00Jianchun (JC) Wang5  E B Distribution D    D  

05/12/00Jianchun (JC) Wang6  b 2 Distribution D    D  

05/12/00Jianchun (JC) Wang7 The D    Final State D    D   88  1492  18

05/12/00Jianchun (JC) Wang8 The  Side bands The  side bands:  M   M   Only D   channel shown

05/12/00Jianchun (JC) Wang9 Reconstruction Efficiency D    (~4.6)D   (~6.4)

05/12/00Jianchun (JC) Wang10 Br (B  D   )  Efficiency dependence on M  and decay angles considered (small)  Br (B   D   ) = (0.41  0.07  0.04)% Br (B   D +   ) = (0.28  0.05  0.03)%  Systematic errors ( ~ 10%)  5.4% for   2.2% per charged track  5.5% on background shape  Miscellaneous

05/12/00Jianchun (JC) Wang11 The   Mass Distribution Breit-Wigner: Mass = 1418  26  =388  44 MeV  Right plot derived from fit of M B distribution for each bin  Mass window (1.1  1.7 GeV) applied for further study

05/12/00Jianchun (JC) Wang12 Angular Distributions   angle between  in A frame to A boost direction   angle of normal of  decay plane to  boost  angle between planes of A decay and  decay B  D  A  A             spin 0 0 s s helicity

05/12/00Jianchun (JC) Wang13 Angular dependent efficiency Slightly dependent, correction made

05/12/00Jianchun (JC) Wang14 The Angular Distributions For 1 + and 2 , the langitudinal ratio a 0 is floating

05/12/00Jianchun (JC) Wang15 The  2 of Angular Fit Remind:  2 / ndof   40 %

05/12/00Jianchun (JC) Wang16 Summary We have observed D   decays and measured the branching ratio (0.41% for B+, 0.28% for B°) There is   enhancement at 1418±26 MeV that is 388±44 MeV wide, which is consistent with our previous observation in D*   modes. Angular distributions are studied, J P =   is favored The resonance A is most likely  (1440) Combine two CBX together