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Recent Charmonium Results from Ψ(2S) Decays at BESII

Recent Charmonium Results from Ψ(2S) Decays at BESII. Changzheng YUAN IHEP, Beijing for the BES Collaboration. 2nd International Workshop on Heavy Quarkonium Sept. 20 – 22, 2003, Fermilab. BESII obtained 14 M (2S) events. Study of V T channels

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Recent Charmonium Results from Ψ(2S) Decays at BESII

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  1. Recent Charmonium Results from Ψ(2S) Decays at BESII Changzheng YUAN IHEP, Beijing for the BES Collaboration 2nd International Workshop on Heavy Quarkonium Sept. 20 – 22, 2003, Fermilab

  2. BESII obtained14 M (2S) events • Study of V T channels inΨ(2S) decay • First observation of K0S K0LinΨ(2S) decay (and improved analysis of J/  K0S K0L ) • First evidence of   in cJ decay 14 1.5 01.11-02.3

  3. pQCD rule and “ puzzle” • pQCD rule [the relation between J/ and (2S) ] • Violation was revealed by MARK-II , confirmed by BES at higher sensitivity

  4. VT Channel • BES-I results [PRL81(1998)5080] [PRD67(2003)052002] † This value from DM2 only 12 % rule ( pQCD rule ) Suppressed!!

  5. BES Preliminary Ψ(2S)  V T  f2   +–0 +–     +–+–0     a2         +–+–0    Ψ(2S) K* K*2   K K K+K– + –  f2'   K+K– KK K+K–K +K –

  6. Event Selection Ψ(2S)  V T • Four charged tracks with net charge zero; • |cosθ|<0.80 for all tracks; • PartID using TOF+dE/dx • At least 2 photon candidates for π0 channels; • Remove ψ(2S) π﹢π﹣J/ψ background; • Kinematic fit (4C/5C), Prob>0.01. χ2KF of ψ(2S) 5 π Data/MC

  7. BES Preliminary Ψ(2S)  V T M.C. Data B.G.(  ) f2 (1270) B.G.(M.C.)

  8. BES Preliminary Ψ(2S)  V T Data M.C. a2 (1320) B.G.

  9. BES Preliminary Ψ(2S)  V T Data M.C. K*(892) K*2 (1430) B.G.

  10. BES Preliminary Ψ(2S)  V T M.C. Data f2'(1525) f0(980) B.G.

  11. BES Preliminary Ψ(2S)  V T

  12. BES Preliminary Ψ(2S)  V T Systematic Errors (%) *NO evidence of continuum production according to study with a 6 pb-1 data sample at Ecm=3.65GeV.

  13. BES Preliminary Ψ(2S)  V T † This value from DM2 only 12 % rule ( pQCD rule ) Suppressed!!

  14. Ψ(2S)  KS KL Theoretical Background • pQCD rule & Phase Study B(2S) Ks K L Phase

  15. Ψ(2S)  KS KL The Relative Phase 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(2S)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, hep-ph/0303144.

  16. Ψ(2S)  KS KL The Relative Phase Ψ(2S)  Pseudoscalar Pseudoscalar A’ (π﹢π﹣) and A’+B’ (K﹢K﹣) known, KS KLis needed to extract the phase between A’ and B’. φ

  17. BES Preliminary Ψ(2S)  KS KL – + – + – + KL

  18. BES Preliminary Ψ(2S)  KS KL • Two Good charged tracks with net charge zero ; • Decay length in transverse plane greater than 1.0 cm for KS ID; • Total Energy of photon candidates less than 1 GeV.

  19. BES Preliminary Ψ(2S)  KS KL 14M ψ(2S) Bkg MC signal Ks mass sidebands

  20. BES Preliminary Ψ(2S)  KS KL Systematic Errors Lxy Eγtot cosθ VC trigger

  21. BES Preliminary Ψ(2S)  KS KL

  22. BES Preliminary J/Ψ  KS KL 58M J/ψ signal MC Bkg K*0KS+c.c. Ks mass sidebands

  23. BES Preliminary J/Ψ  KS KL ~4σ diff. PDG2002: BJ/ Ks K L = ( 1.08 ± 0.14)10 – 4

  24. J/Ψ , Ψ(2S)  KS KL B(2S) Ks K L= (5.25± 0.45± 0.63 )  10 – 5 BJ/ Ks K L = (1.86 ± 0.04± 0.14 )  10 – 4 Ψ(2S) enhanced!

  25. B ((2S) KS KL ) =5.2510 – 5 Ψ(2S)  KS KL K+K– & +  inputs ; Input 1:DASP; Input 2:BESI ; Input 3: K+K– from BESI & + by form factor. PLB567 (2003)73 –80° 120 °

  26. COM for cJB B-bar • B(cJ pp-bar) fromBES, PRL81, 3091 (1998); • E760, NPB373, 35 (1992); R704, PLBB172, 455 (1986) • Nucleon wave function at small Q2: J.Bolz, P. Kroll, Z. Phys. A356, 327 (1996) J.Bolz, P. Kroll, Eur. Phys. J. C2, 454 (1998) For each s quark, introduces S. M. Wong, Eur. Phys. J. C14, 643 (2000)

  27. Event Selection Final states: γπ＋π－pp-bar γ

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

  29. cJ Signal Data/Monte Carlo χc2 χc1 χc0

  30. Really ΛΛ? Yes! we have p/p-bar! Yes! we have long decay length!

  31. Remaining backgrounds Monte Carlo Simulation: Monte Carlo prediction and a best fit

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

  33. Number of ψ(2S) events To achieve high precision & cancel out systematic bias =14.9(1±8%)M

  34. Systematic Errors Extensive Comparison Between Data and Monte Carlo Simulation! (Thanks for The Large Data sample!) ~20%!

  35. – 3.1 – 3.4 – 4.0 –1.2 –0.9 –1.3 PRD67, 112001 (2003)

  36. Eur. Phys. J. C 14, 643–671 –1.2 –0.9 –1.3 * The results on c1 and c2 decays only agree marginally with model predictions. * No prediction for c0 .

  37. Discussions Checked with BESII data, no serious discrepancy! • B(χcJp p-bar)? NO! • COM? Possible! Hints from other experiments! • wave functions? Possible! Need other experiment test! E866 BELLE

  38. Summary • Ψ(2S) VT channels f2 ,  a2 , K* K*2 and  f2' are first observed and branching ratios measured. The suppression of VT is confirmed. • First observation of K0S K0Lin Ψ(2S) decay. Improved measurement of J/ψ K0S K0L . Ψ(2S) is enhanced relative to 12% rule. The phase for ψ(2S) PP is ﹣80°or 120°. • First evidence of   in cJ decay . Results disagree with “COM+baryon wave function” calculation. • More results expected from BESIIΨ(2S) sample.

  39. Thanks a lot ! 谢谢!

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