1 / 28

Recent Results on (2S) and  cJ Decays from BES

Recent Results on (2S) and  cJ Decays from BES. Zhiyong Wang IHEP, Beijing ,China for the BES Collaboration. VietNam 2004 5th Rencontres du Vietnam Particle Physics and Astrophysics Hanoi August 5 to August 11, 2004. BESII Detector.

gilles
Download Presentation

Recent Results on (2S) and  cJ Decays from BES

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 on (2S) and cJ Decays from BES Zhiyong Wang IHEP, Beijing ,China for the BES Collaboration VietNam 20045th Rencontres du Vietnam Particle Physics and Astrophysics Hanoi August 5 to August 11, 2004

  2. BESII Detector VC: xy = 100 m TOF: T = 180 ps counter: r= 3 cm MDC: xy = 220 m BSC: E/E= 22 % z = 5.5 cm dE/dx=8.5 % = 7.9 mr B field: 0.4 T p/p=1.7%(1+p2) z = 3.1 cm

  3. BESII obtained14 M ’ events 14M • ’ VP • ’ VT • ’ PP (K0S K0L) • J/-contained • cJ  , pp, f0f0 • Other ’ and cJ decays Nov.01-Mar.02 3M

  4. “pQCD rule”and“ puzzle” • pQCD rule (12% rule) [the relation between J/ and ’ ] • Violation was revealed by MARK-II , confirmed by BES at higher sensitivity. • Provide information for understanding the charmonium decay dynamics. MARK-II K*K ρπ

  5. The Relative Phase φ J/ψ Decays: 1. AP: 90 ° M. Suzuki, PRD63, 054021 (2001) 2. VP: (106 ±10) ° J. Jousset et al., PRD41, 1389 (1990) D. Coffman et al., PRD38, 2695 (1988) N. N. Achasov, talk at Hadron2001 3. PP: (90 ±10) ° M. Suzuki, PRD60, 051501 (1999) 4. VV: (138 ±37) ° L. Köpke and N. Wermes, Phys. Rep. 74, 67 (1989) 5. NN: (89 ±15) ° R. Baldini et al., PLB444, 111 (1998) ψ’VP 1. φ=180 °(90 ° ruled out!) M. Suzuki, PRD63, 054021 (2001) 2. φ=﹣90 ° or φ=180 °(with continuum amplitude) P. Wang, C. Z. Yuan and X. H. Mo, PRD69, 057502 (2004)

  6. Measure the relative phase in e+e – experiment φ phase interference interference Take the continuum contribution and its interference effect into consideration , we could determine not only the magnitudebut also the sign of the phase.

  7. In this talk, I will cover • ’ VP K*+K-+c.c., K*0K0+c.c., 0 • ’ VT  f2 ,  a2 , K* K*2 ,  f2' • ’ PP K0S K0L (also J/ decays) for pQCD rule and phase study!

  8. BES preliminary! ’ VP K*(892)K+c.c. K* B.G. K*2(1430) K*0 K*0 65.6±9.0 evts, 11σ Br0=(15.0±2.1 ±1.9)10–5 K*2(1430) K* Br± =(2.9±1.3 ±0.4)10–5 B.G. 9.6±4.2 evts, 3.5σ First observation! Large Isospin violation!

  9. 0 ’ VP BES preliminary! Expects 22 continuum background events in ’ sample! 7.4 ±2.8 evts. 0 B.G. 31.2 ±7.2 evts. B.G. 0 @3.650GeV& L=(6.42 ±0.24) pb 1 Information on continuum data is very important for ’ analyses! @3.686GeV& L=(19.72 ±0.86) pb 1

  10. ’ V P • BES-II results (Preliminary) Suppressed !! 12% rule Large isospin violation indicates EM decay important!

  11. ’ V T  f2   +–0 +–     +–+–0     a2         +–+–0    ’ K* K*2   K K K+K– + –  f2'   KKKK K+K–K +K –

  12. ’ V T B.G.(  ) a2 (1320) f2 (1270) B.G. B.G.(M.C.) f0(980) K*(892) f2'(1525) B.G. K*2 (1430) B.G.

  13. ’ V T † This value from DM2 only Suppressed!! PRD69, 072001 (2004) 12 % rule( pQCD rule )

  14. ’  KS KL 14M ψ(2S) Bkg MC signal Ks mass sidebands PRL 92, 052001 (2004)

  15. J/ KS KL 58M J/ψ signal MC Bkg K*0KS+c.c. Ks mass sidebands PRD 69, 012003 (2004)

  16. ’  KS KL First measurement of the phase in ’ decays! B (’KS KL ) =5.2410 – 5 K+K– & +  inputs ; Input 1:DASP; Input 2:BESI ; Input 3: K+K– from BESI & + by form factor. Yuan, Wang, Mo: PLB567 (2003)73 –(8229)° (12127)°

  17. J/ , ’ KS KL B ’ Ks KL= (5.24± 0.47± 0.48 )  10 – 5 B J/ Ks KL = (1.82 ± 0.04± 0.13 )  10 – 4 B(’) enhanced!

  18. ’ J/-Contained Motivation:Improve Exp. Precisionand Test Theory Calculation Inclusive Method [BES-I] XJ/ , J/  +  – ---------------------------------------------------------- AnythingJ/ 00 J/ J/  c1 , c1 J/  c2 , c2 J/ Exclusive Method [BES-II] J/ , J/ l+ l – ----------------------------------------------------- 0 J/ J/  c1 , c1 J/  c2 , c2 J/ Phys.Rev.D70:012003,2004 Phys.Rev.D70:012006,2004

  19. c1 c2 J/ First measurement B(´00 J/)=(18.2± 1.2)% oJ/ BES XJ/ BES measures the BRs in high precision!

  20. ’ J/ Discussions PCAC [G. A. Miller, Phys. Rep. 194,1(1990)]: Casalbuoni et al: improved expression [PLB 309,163(1993)] BES result:R=0.048±0.007 QCD Multipole Expansion & BTG potential model [Y. P. Kuang, PRD24, 2874(1981), ibid. 37, 1210(1988) BES (+PDG for ): R<0.0098 R<0.0065

  21. Λ signal in πp mass Monte Carlo Data Clear Λ Λ-bar Signal

  22. Fit the mass spectrum MC efficiencies χc1 χc2 χc0 ΛΛ-bar Mass (GeV)

  23. Final states: γpp-bar c0 c1 c2 PRD69, 092001(2004)

  24. Evidence for c0 f0f0 c2 preliminary! c0 KsKs  c0f0(980) f0(980) No c2f0(980) f0(980)

  25. c0f0(980) f0(980) preliminary! Two entries/event f0(980) recoil mass (m=0.93-1.03 GeV) f0(980) side bands events recoil mass • Strong evidence for • c0f0(980) f0(980) • 4.6 • B(c0f0f0, f0+-) • =(7.5±1.9±1.7) ×10-4

  26. Final states with KSKS in’ decays From 14M ’(preliminary!) Many channels are first observation, useful for comparing with Isospin conjugate final states!

  27. Summary • ’ VP channelsK* Kand are first observed. Large isospin violation effect in K* K mode. BES confirms the VP suppression in ’ decays. • ’ VT channels  f2 ,  a2 , K* K*2 and  f2' are first observed and branching ratios are measured. All are suppressed in ’ decays. • First observation of K0S K0Lin ’ decay. Improved measurement of J/ψ K0S K0L . ’ is enhanced relative to the pQCD 12% rule. • ’ J/-contained final states are to improve experimental precision and test theoretical predications. • cJ   , f0f0 and p p are measured and cJ   , f0f0 are first observed. • Other ’ and cJ decays are also measured and some of them are first observed

  28. Thanks a lot ! 谢谢!

More Related