1 / 24

Recent Results of J/  and (2S) at BESII

Recent Results of J/  and (2S) at BESII. Zhiyong Wang IHEP, Beijing for the BES Collaboration. Rencontres de Moriond 2007 QCD and High Energy Hadronic Interactions La Thuile, Italy, 10 – 24, March. Outline. J/  results Wide resonance X(1580). Threshold enhancement in J/ 

ekram
Télécharger la présentation

Recent Results of J/  and (2S) at BESII

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. Recent Results of J/ and (2S) at BESII Zhiyong Wang IHEP, Beijing for the BES Collaboration Rencontres de Moriond 2007 QCD and High Energy Hadronic InteractionsLa Thuile, Italy,10 – 24, March

  2. Outline • J/ results • Wide resonance X(1580). • Threshold enhancement in J/ • ,  invisible • (2S) results • Hadronic decay • Radiative decay • (2S)+ • cJ decay Moriond QCD ,2007

  3. Data samples 28M J/ (2S) 14M 4M 6.42 pb-1 continuum data at Ecm=3.65 GeV for background study. Moriond QCD ,2007

  4. J/ results Moriond QCD ,2007

  5. New Observations at BESII In past three years, a number of new structures were observed at BESII • A possible bound state: mass threshold enhancement in and new observation of X(1835) in . • mass threshold enhancement in • mass threshold enhancementin In this talk, I will report two new structures  Moriond QCD ,2007

  6. Observation of X(1580)inJ/  K+K- 0 Background Moriond QCD ,2007 PRL97,142002(2006)

  7. How to understand broad X(1580)? • Search of a similar structure in J/  KSK will help to determine its isospin. • X(1580) could have different nature from conventional mesons: • Width is much broader than other mesons. • Broad width is expected for a multiquark state. Moriond QCD ,2007

  8. Observation of  mass threshold enhancement in J/ • We studied DOZI process: J/    +  +    +-0 K+ K-    recoiling against  Moriond QCD ,2007

  9. Observation of  mass threshold enhancement in J/ background X(1810) M2(g) M2(gw) M() Spin-parity favors 0++ Phys. Rev. Lett., 96 (2006) 162002 Possible interpretations: Multiquark, Hybrid, Glueball Moriond QCD ,2007

  10. Searching for /’ Invisible Decays Via J//’ • Reconstructing K+K , • looking at missing momentum of  decays • Fast  (1.2 GeV) will help us define the decay • direction of invisible decay of / (958) . Missing direction Tag direction No any hit information are required outside of the core of  decays. Signal MC 58 M J/  missing momentum distribution PRL97,202002(2006) Moriond QCD ,2007

  11. (2S) results Moriond QCD ,2007

  12. (2S) hadronic decay M. Appelquist and H. D. Politzer, PRL34, 43 (1975) Moriond QCD ,2007

  13. ’ 3-body PRD71,072006(2005);PRD74, 12004 (2006) 256±18 44.8±8.7 914±42 921±40 Moriond QCD ,2007

  14. BESII: PRD71, 072006 (2005) ’ 3-body BESII: PRD74, 12004 (2006) Moriond QCD ,2007

  15. Multi-body ’ decays BESII, PRD73, 052004 (2006) Moriond QCD ,2007

  16. Multi-body ’ decays Many intermediate states are observed for the first time. Moriond QCD ,2007

  17. (2S) radiative decay Many channels for (2S)+hadrons with the invariant mass of hadrons below 2.9GeV have been studied. Hep-ex/0612016 Moriond QCD ,2007

  18. Search for the strong mass threshold enhancement X(1860) in • No obvious strong mass threshold enhancement was observed in • A strong mass threshold enhancement was observed in +3 +5 -10 -25 M=1859 MeV/c2 G < 30 MeV/c2 (90% CL) acceptance Fit acceptance 0 0.1 0.2 0.3 X(1860) M(pp)-2mp (GeV) Moriond QCD ,2007

  19. (2S) radiative decay PRD74, 072001(2006) Moriond QCD ,2007

  20. Accepted by PLB B(BBbar) According to the hadron helicity conservation, the angular distribution of J/，(2S)B8B8 satisfy: Moriond QCD ,2007

  21. (2S)+ PRD74, 112003(2006) Moriond QCD ,2007

  22. cJ decay Most channels are measured for the first time Moriond QCD ,2007

  23. cJK+ K K+ K cJ++ ppbar cJ+K,+ Moriond QCD ,2007

  24. Summary • A wide 1-- resonance X(1580) is observed in J/K+K0 . • The mass threshold enhancement is observed in J/. • The invisible decay mode is studied for  and  via J//. • A lot of (2S) radiative and hadronic decay channels are measured and the 12% rule are tested. • Many cJ decay modes are observed and most are measured for the first time. Thanks a lot ! Moriond QCD ,2007

More Related