1 / 24

Study of B D S ( * ) + D* ( * ) and D ( * ) (4) - at CLEO

DPF 2000 Aug 9 - 12 , 2000 Columbus, Ohio. Study of B D S ( * ) + D* ( * ) and D ( * ) (4) - at CLEO. Jianchun Wang Syracuse University Representing The CLEO Collaboration. Introduction.

jcalkins
Download Presentation

Study of B D S ( * ) + D* ( * ) and D ( * ) (4) - at CLEO

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. DPF 2000 Aug 9 - 12 , 2000 Columbus, Ohio Study of BDS(*)+D*(*)and D(*) (4)- at CLEO Jianchun Wang Syracuse University Representing The CLEO Collaboration

  2. 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/y K(*), DS(*)D(*), D(*)(np)-) • 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 Jianchun (JC) Wang

  3. p DS B° D* D DS a p qp D* D Partial Reconstruction of BDS+D*- • Features of the decay: DSD* back-to-back, p follow D* direction • Full reconstruction of DS(DSfp+, fK+K-) andp • 8 unknown, 8 constraint 2 solutions (quadratic ambiguity) • Parameters used in the fit (independent on the choice): • a: angle between -pDs and pp • a0: lower kinematic limit of a • pDs: magnitude of DS momentum • qps: decay angle of slow p in D* frame p Jianchun (JC) Wang

  4. Distribution of cosa0- cosa • Signal: DS(*)+D*-, DS(*)+D**, DS(*)+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 • DS(*)+D*(*): 314.0  24.0 BB background: 138.9  5.2 continuum: 74.8 cosa0 - cosa Jianchun (JC) Wang

  5. Separation of Signals DS+D*-DS*+D*-DS(*)+D**DS(*)+D**- • Fit in two-dimensional space: pDsand cosqp • Total 4 parameters in the 2-D fit: • # of DS+D*- (D*- is longitudinally polarized) • # of DS*+D*-GL / G • # of DS(*)+D** (mixture of 12 modes) Jianchun (JC) Wang

  6. DS momentum (GeV) cos qp Projection of 2-D Fit c2 = 125.4 for ndof=130-4, CL=84.1% DS(*)D** ( 81.6  23.4 ) Jianchun (JC) Wang

  7. DS momentum (GeV) cos qp 2-D fit without DS(*)+D** c2 = 139.9 for ndof =130-3 Jianchun (JC) Wang

  8. Results from 2D Fit • Fitted yield: • # of DS+D*-: 92.7  14.3  9.3 • # of DS*+D*-: 149.2  30.4  20.3 • # of DS(*)+D**: 81.6  23.3  14.8 • Branching fractions: • B (B°DS+D*-) = ( 1.10  0.18  0.11  0.28 ) % • B (B°DS*+D*-) = ( 1.82  0.37  0.25  0.46 ) % • B (B+DS(*)+D**°) = ( 2.73  0.78  0.51  0.68 ) % • DS*+D*-: GL / G = ( 50.6  13.9  3.6 ) %, consistent with factorization prediction of 54% Uncertainty on B (DS) Jianchun (JC) Wang

  9. EB sidebands signal 35829 Full Reconstruction ofBD*+p+p-p-p B°D*++--°, D*+D°+(D° K-+, K-+°, K-++- ) Fit B yield in each Mpppp bin Similar spectra observed in D*°(4p)- Jianchun (JC) Wang

  10. w Mppp (GeV) The p+p-pMass Distribution • What are the decay mechanisms for the (4p)- final state ? • Examine the p+p-p°mass spectrum (2 combinations/event). All 3 D° decay modes summed Enlarged & Dalitz plot exterior removed Jianchun (JC) Wang

  11. D*+wp- D*wp- All 3 Do decays used onlyDoK-+ The wp- Mass Distribution • Possible resonance ( temporarily called A ) • Simple BW fit: M=141933 MeV, =38244 MeV Jianchun (JC) Wang

  12. Spin-0 expectation D*+(wp)- Angular Distributions • For a spin-0 A, the D* & w would be fully polarized • Spin 0 c2/dof = 3.5 (cosqD*), 22 (cosqw)  Ruled out • Best fitGL/G = 0.630.09 (D*+), 0.100.09 (w) Jianchun (JC) Wang

  13. EB sidebands EB sidebands Signal 9118 Signal 8814 The Dwp-Final State Dwp- (DoK-+) D+wp- (D+K-++) • Signal: |DE|<2s (18MeV) Sideband: 3s<|DE|<7s • No signal in w sidebands Jianchun (JC) Wang

  14. The wp- Mass Distribution Breit-Wigner: Mass = 141543 =419110 MeV • Dwp-and D+wp- modes combined (179 events) • Consistent with D*wp result • Combine D*wp and Dwp fit results: mass = 14182619 MeV G = 3884132 MeV Jianchun (JC) Wang

  15. The Angular Distributions inB  D A-:A- w p-,w pp+p-  between w in A frame & A boost direction  between normal of w decay plane & w boost  between A & w decay planes • Small efficiency corrections applied • For 1+ and 2-, the longitudinal ratio (GL/G) floats • 1-preferred, c2/dof (1-) = 1.7, (2+) = 3.2 Jianchun (JC) Wang

  16. Identifying the A- with the r • Variety of resonances in between 1-2 GeV, which are poorly studied due to limited statistics or wide width • Clegg & Donnachie: (t(4p)n, e+e-p+p-, p+p+p-p-) find two 1- states with (M, G) = (146325, 31162) MeV & (173030, 400100) MeV, only the lighter one decays to wp , mixed with non-qq states • Godfrey & Isgur: Predict first radial excited r at 1450 MeV, G=320 MeV, B (wp)=39% Jianchun (JC) Wang

  17. Evidence for r from t Decay t-wp-n t-pp-n CLEO CLEO w signal r’ r w sidebands Difficult to ascertain the Mass and Width Jianchun (JC) Wang

  18. Summary & Discussion of Rates • r dominates the wp final state • G(BD) / G(BD) = 1.04  0.21  0.06 G(BD) / G(BD) = 1.10  0.31  0.06 G(BD) / G(BD) = 1.06  0.17  0.04 Consistent with Heavy Quark Symmetry prediction ( ratio = 1 ) • With B (wp)=39%, G(BD(*)) ~ G(BD(*)) Preliminary Jianchun (JC) Wang

  19. D*+ + GL/G (%) r- 87.85.3 r- 63  9 DS*- 50.613.93.6 Factorization Test • Factorization:GL/G (BD+h) = GL/G (BD+ln)|q2=mh2 • Excellent agreement between measurements and predictions Jianchun (JC) Wang

  20. Model-dependent Decay Constant of  • G(BD+h) / dG/dq2(BD+ln)|q2=mh2= 6p2c12fh2 |Vud|2, c1=1.1±0.1 • Measurement: f2 B (wp) = 0.011 ± 0.003 GeV2 • Godfrey & Isgur predict: B (wp) = 39% • Our measurement f = 167 ± 23MeV ( f  220 MeV ) Jianchun (JC) Wang

  21. Summary • Branching fraction of B  DS(*)D*(*) measured • Large branching rate of B  D*p+p-p-p, D*wp-,and Dwp-modes found • For first time, r observed in B decays (hep-ex/0006018) • Coupling large, may be similar to r • Relatively clean place to establish r mass and width, we find M = 1418±26±19 MeV, G = 388±44±32 MeV • GL / G ( BD*h- ) for h=r, r, and DS*- consistent with factorization predictions • G(BD*-) / G(BD-) satisfy HQET Jianchun (JC) Wang

  22. Distribution of cosa0 - cosa Jianchun (JC) Wang

  23. Distribution of Ds momentum Jianchun (JC) Wang

  24. Distribution of cosqp Jianchun (JC) Wang

More Related