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Semileptonic D Decays from CLEO and BELLE

Semileptonic D Decays from CLEO and BELLE. Yongsheng Gao Southern Methodist University (CLEO Collaboration) ICHEP04, Beijing, Aug. 16 ─ 23, 2004. CLEO. ICHEP Abstract/Paper. CLEO-III Exclusive D 0 semileptonic Decays (ICHEP ABS11-0780, CLEO CONF 04-14).

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Semileptonic D Decays from CLEO and BELLE

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  1. Semileptonic D Decays from CLEO and BELLE Yongsheng Gao Southern Methodist University (CLEO Collaboration) ICHEP04, Beijing, Aug. 16 ─ 23, 2004 CLEO

  2. ICHEP Abstract/Paper • CLEO-III Exclusive D0 semileptonic Decays • (ICHEP ABS11-0780, CLEO CONF 04-14) • First CLEO-c Inclusive D0,D+ semileptonic Decays • (ICHEP ABS11-0777, CLEO CONF 04-12) • First CLEO-c Exclusive D0 semileptonic Decays • (ICHEP ABS8-0781, CLEO CONF 04-3) • BELLE Exclusive D0 semileptonic Decays • (ICHEP ABS11-0706, BELLE CONF 0457) Yongsheng Gao

  3. Outline • Introduction • CLEO-III Semileptonic D Decay Results • Exclusive D0  K-l+n, -l+n (ICHEP ABS11-0780, CLEO CONF 04-14, Submitted to PRL) • First CLEO-c Semileptonic D Decay Results • Inclusive D0  Xe+n, D+  Xe+n (ICHEP ABS11-0777) • Exclusive D0  K-e+n, -e+n, K*-e+n, ρ-e+n (ICHEP ABS8-0781, CLEO CONF 04-3) • Future Outlook Yongsheng Gao

  4. Why Semileptonic D Decay? • D0  Xe+n and D+  Xe+n: • Inclusive semileptonic BR and spectrum • D0  K-e+n, -e+n etc: • Form Factors, Vcd , Vcs and Vub Yongsheng Gao

  5. CESR and CLEO Tracking: Drift Chambers Electron ID: CsI Cal. Hadron ID: RICH Yongsheng Gao

  6. CLEO Data Samples y(2S) y(3770) Mass (GeV/c2) Yongsheng Gao

  7. CLEO III D0 K- l+n/- l+n ~7 fb-1 of CLEO-III data near (4S) Event Reconstruction:D*++slowD0 Observable: M = MD* - MD0 (K) l  D0 l D0Kl No PID D0Kl 2% K-faking-, 87%  efficiency D0 l M (GeV) K/ Separation Capability Essential! Yongsheng Gao

  8. CLEO III D0 K- l+n/- l+n ~7 fb-1 CLEO III data near (4S) Kln pln =0.0820.006(stat)0.005(sys) Submitted to PRL Existing Measurements: CLEO III E687 1996 CLEO II 1995 MarkIII 1988 Yongsheng Gao

  9. CLEO III D0 K- l+n/- l+n pen Ken Submitted to PRL First Measurement Yongsheng Gao

  10. Charm at Y(3770) vs ~(4S) Y(3770) ~(4S)  K- K+ - • Large Cross-Section • Low Multiplicity • NO Fragmentation • Kinematics Variables: • “Background Free” e+ ∆E = Eb - ED U = Emiss - Pmiss Yongsheng Gao

  11. K-,-,K*-,ρ- or X e+ D0  Unique Kinematics at Y(3770) No PID e+ e  D0 Tag K+ - Yongsheng Gao

  12. Fully Reconstructed D0 (Tag) 60K fully reconstructed D0 From 60 pb-1 at Y(3770) Preliminary Yongsheng Gao

  13. Electron Identification Radiative Bhabha E/p, dE/dx, RICH Preliminary Yongsheng Gao

  14. Corrected Electron Spectra From 60 pb-1 of first CLEO-c data: Preliminary CLEO-c DATA CLEO-c DATA Number Of event /(50MeV/c) Number Of event /(50MeV/c) • D0  Xe+n • D+  Xe+n Electron Momentum (GeV/c) Electron Momentum (GeV/c) Stat. Uncertainty ~0.5% PDG: BR = (6.750.29)% Stat. Uncertainty ~ 0.6% PDG: BR = (17.21.9)% Yongsheng Gao

  15. Crossfeed bw D0  K-e+n, -e+n ~(4S): NO separation in ∆M Y(3770): WELL separated in U Y(3770) ~(4S) • D0-e+n No PID No PID • D0K-e+n D0Kl D0 l 0.12 0.22 M (GeV) Yongsheng Gao

  16. CLEO-c: D0  K-e+n Results From 60 pb-1 CLEO-c data: Preliminary Yongsheng Gao

  17. CLEO-c Exclusive D0 Semileptonic • D0-e+n • D0K-e+n Preliminary • D0K*-e+n • D0ρ-e+n First Observation Yongsheng Gao

  18. First CLEO-c Results Preliminary • Improved measurements of absolute Branching Fractions • First Observation of D0  ρ-e+n • Both Statistic/Systematic errors limited by the 60 pb-1 data! • Expect ~3 fb-1 of CLEO-c data in one year! Yongsheng Gao

  19. Summary “Background Free” at Y(3770) Limiting Factor:60 pb-1 of data sample! Many very precision charm results: Form factors, Absolute BR, CKM elements … Yongsheng Gao

  20. 2005:y(3770) ~ 3 fb-1 18 million DD evts, 3,6 milliontaggedD decays (150 times MARK III) C L E O c 2006: MeV ~ 3 fb-1 1.5 million DsDs evts, 0.3 milliontaggedDs (480 times MARK III, 130 times BES) 2007:y(3100), ~1 fb-1 & y(3686) ~ 1 Billion J/y decays (170 times MARK III, 20 times BES II) CLEO-c Outlook Many very precision charm results: Form factors, Absolute BR, CKM elements … CLEO-c Yellow Book, CLNS-01/1742 Yongsheng Gao

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