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Experimental results in charmonium decays from BES

Experimental results in charmonium decays from BES. Rong-Gang Ping (presented by F. Harris) for BES collaboration Charm 2007 Aug. 6, 2007. (2s) data samples. outline. ’ decays Leptonic decays Radiative decays Hadronic decays  cJ decays VV PPP. 26M. 14M. 4M. 3M.

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Experimental results in charmonium decays from BES

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  1. Experimental results in charmonium decays from BES Rong-Gang Ping (presented by F. Harris) for BES collaboration Charm 2007 Aug. 6, 2007

  2. (2s) data samples outline • ’ decays • Leptonic decays • Radiative decays • Hadronic decays • cJ decays • VV • PPP 26M 14M 4M 3M Also 6.42 pb-1 of data at Ecm=3.65 GeV for background study.

  3. Expected? Sequential lepton hypothesis:

  4. BESII: remeasure with larger sample • Measured in     ee • Characterized by • 2 charged tracks; 1  and 1 e • missing energy and momentum • no extra hits in BSC  = 17.8%

  5. BESII    Result: B(  ) = (3.100.210.38) x 10-3 Lepton universality is tested in charmonium decays. PRD 74: 112003 (2006)

  6. ’ radiative decays PRL 99, 011802 (2007)

  7. Observation of ’ radiative decays • Expect ~1% BR, but only 0.05% previously observed. • Potential channels for hadron spectroscopy study, including search for non-qqbar states, if enough statistics. • ~ 0.1% more observed in this analysis. PRL99, 011802 (2007)

  8. PRD74, 072001 (2006).

  9. PRD74, 072001 (2006).

  10. MARK-II K*K ρπ

  11. x 10-4 x 10-4 Angular distribution: 2

  12. Baryonic decays Rich structure (N*s), statistics (~850 evts in each mode). Still low for a partial wave analysis. PRD74, 012004 (2006)

  13. Test I-spin symmetry (prediction: 1:2:2)

  14. PRL 99,011802 (2007)

  15. Pair production of vectors PLB642, 197 (2006) c0 c1 c2 Improved precision over PDG (BESI) results on cJKKKK and . First measurement of cJKK. cJ→2(K+K)

  16. c1 c2 cJ decays into PPP PRD74, 072001 (2006) cJ→KK and  c1→KSK+-+c.c. K* PRD 74, 072001 (2006) c0→PPP is suppressed by spin-parity selection;

  17. Nsig=418± 60 h c1→ +- Nsig=222±28 (8.8s) Nsig=58± 14 (4.5s) h sideband a0 sideband

  18. BES: cJ→KK and  PRD 74, 072001 (2006) CLEO-c, PRD75, 032002

  19. arXiv: 0707.1127 [hep-ex] Submitted to PRD ’(J/) +0/ • Is it really B(0)>B()? background from J/  ΣΛπ signal First measurement!

  20. Summary • ’ leptonic decays, hadronic decays, radiative decays are studied to search for new phenomena and to test QCD predictions. • c decays are studied using ’ data sample. • CLEOc will take the leading role in ’ and c decays; we are now preparing for the BESIII data taking and the physics analysis. Thanks a lot !

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