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

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Presentation on theme: "Experimental results in charmonium decays from BES Rong-Gang Ping (presented by F. Harris) for BES collaboration Charm 2007 Aug. 6, 2007."— Presentation transcript:

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   ’ decays  Leptonic decays  Radiative decays  Hadronic decays   cJ decays  VV  PPP 3M 14M 4M outline 26M 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 B ee (10 -3 )B  (10 -3 )B  /0.3885 (10 -3 ) 7.35  0.387.3  0.88.0  1.1 Lepton universality is tested in charmonium decays. PRD 74: 112003 (2006)

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7  ’ radiative decays PRL 99, 011802 (2007)

8 Observation of  ’ radiative decays Mode BR (  10 -5 ) [m<2.9 GeV/c 2 ]  pp-bar 2.9 ± 0.4 ± 0.4  ’ ’ 12.6 ± 2.9 ± 1.5  2(  +  - ) 39.6 ± 2.8 ± 5.0  K S K +  - +c.c. 25.6 ± 3.6 ± 3.6  +-K+K- +-K+K- 19.1 ± 2.7 ± 4.3   +  - ppbar 2.8 ± 1.2 ± 0.7  2(K + K - ) < 4.0  3(  +  - ) < 17  2(  +  - )K + K - < 22 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)

9 PRD74, 072001 (2006).

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11 K*K ρπ MARK-II

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13 x 10 -4 Angular distribution: 2

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

15 Test I-spin symmetry (prediction: 1:2:2)

16 PRL 99,011802 (2007)

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

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

20 N sig =418 ± 60  Nsig=58 ± 14 (4.5  )N sig =222 ±28 (8.8  )  sideband a  sideband  c1 →  +  -

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

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

23   ’ 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. Summary Thanks a lot !

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