Recent Results of ?(2S) Decays at BESII

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Recent Results of ?(2S) Decays at BESII

• ???
• IHEP, Beijing
• for the BES Collaboration

??????????? ??,??
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Outline

• ?(2S)????
• 12 rule
• ?(2S)?3-body
• ?(2S)?pn??,pn??
• ?(2S)?????0KK?
• ???BB

?
?
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Events selection and result
Data MCcont.Bg. Cont.Bg. Bg.
BESII
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M. Appelquist and H. D. Politzer, PRL34, 43 (1975)
This is the famous (or notorious) 12
rule.
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12 rule

• 3-body
• Multi-body
• Radiative decay

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?? 3-body
PRD74, 12004 (2006)
92140
91442
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BESII PRD71, 072006 (2005)
?? 3-body
BESII PRD74, 12004 (2006)
Suppressed!!
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Multi-body ? decays
BESII, PRD73, 052004 (2006)
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Multi-body ? decays
BESII, PRD73, 052004 (2006)
Some modes are suppressed, some are enhanced,
while some others obey the 12 rule!
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PRD, 74(072001)
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Summary 12 rule

• Facts
• ? ?VP suppressed
• ? ?PP enhanced/supressed
• ? ?VT suppressed
• Multi-body obey/sup
• Radiative enhanced/supressed

Seems no obvious rule to categorize the
suppressed, the enhanced, and the normal decay
modes of J/? and ?.
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• The difference between previous BES-I measurement
  and recent CLEOc is significant
• According to the hadron helicity conservation,
  the angular distribution of J/?,?(2S)?B8B8
  satisfy

Channel BES-I(?10-4) CLEOc
2.16?0.15?0.36 2.87?0.12?0.15
1.81?0.20?0.27 3.28?0.23?0.25
1.2?0.4?0.4 2.63?0.35?0.21
0.94?0.27?0.15 2.38?0.30?0.21
?
(?(2S)?ppbar) (?(2S)?ppbar) (?(2S)?ppbar) (?(2S)?ppbar)
Theo. Theo. Exp. Exp.
0.58 Claudson et al 0.67?0.15?0.04 E835
0.80 Carimalo 0.67?0.15?0.04 E835
??1 indicates the baryon isnt point-like
particle.
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• Ngood charged2
• Two tracks are identified as proton or
  anti-proton.
• and
• t-t-lt4ns
• ?acollt5o
• Egt0.75GeV
• EE?-3.686lt0.13GeV

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Angular distribution
?0.82?0.17
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• PID, 2 of 4 good charged tracks with high
  momentum are taken as proton and anti-proton, the
  other two are pion.
• Secondary vertex finding
• Total energy
• Pmisslt0.18GeV

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Suppressing ??? ?? J/?
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Branching ratio of
The B(???p) has been considered in generator.
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• PID and second vertex finding are same as above
  channel.
• Pmisslt0.25GeV
• N?gt2
• 4-C fit,
• Determine pair by minizing

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Branching ratio of
The B(????) has been considered in generator.
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• 6 good charged. The two tracks with higher
  momentum are taken as proton and anti-proton. The
  other 4 tracks are taken as pions.
• At least one of 4 combinations
  can pass the secondary vertex finding algorithm,
  if more than one, the one with the least
  will be selected.
• Pmisslt0.15GeV

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Branching ratio of
The B(????) has been considered in generator.
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Systematic error

• Track efficiency
• Hadronic interactive model
• Uncertainty of background
• ? vertex finding
• ? decay length
• Kinematic fit
• PID
• Energy cut
• Recoiling mass and Pmiss cut.
• ?(2S) total number

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Total systematic error
Channel(?(2S)?)
() 7.1 9.4 13.4 10.3
Results of ?(2S)?BBbar
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Comparison between BES-II and CLEOc for
?(2S)?BBbar
Channel BES-II(?10-4) CLEOc
3.31?0.09?0.23 2.87?0.12?0.15
3.39?0.20?0.32 3.28?0.23?0.25
2.35?0.36?0.32 2.63?0.35?0.21
3.00?0.42?0.31 2.38?0.30?0.21
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Summary

• is improved.
• Many intermediate states are observed in
• such as ?,?,K,f0(1710).
• are
  studied.
• with 4 final states
  are measured and our results are very consistent
  with CLEOcs. The measured ? value in ppbar
  agrees well with one of theoretical predictions.

Thank you!