1. Recent Results of (2S) Decays at BESII
王至勇
IHEP, Beijing
for the BES Collaboration
第七届全国高能物理年会
广西，桂林
ICHEP06,July 26 - August 2, 2006

2. Outline (2S)+ 12% rule BB (2S)3-body (2S)pn,pn
(2S)+0K+K
BB  

5. Events selection and result
Data
MC+cont.+Bg.
Cont.+Bg.
Bg.
BESII

6. M. Appelquist and H. D. Politzer, PRL34, 43 (1975)
This is the famous (or notorious)
“12% rule”.

7. “12% rule”
3-body
Multi-body
Radiative decay

8. ’ 3-body
PRD74, (2006)
921±40
914±42

9. ’ 3-body Suppressed!! BESII: PRD71, 072006 (2005)

10. Multi-body ’ decays
BESII, PRD73, (2006)

11. Multi-body ’ decays
BESII, PRD73, (2006)
Some modes are suppressed, some are enhanced, while some others obey the 12% rule!

13. PRD, 74(072001)

14. 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 ’.

15. Channel BES-I(10-4) CLEOc ((2S)ppbar) Theo. Exp.
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)
Theo.
Exp.
0.58
Claudson et al
0.670.150.04
E835
0.80
Carimalo
1 indicates the baryon isn’t point-like particle.

16. Ngood charged=2
Two tracks are identified as proton or anti-proton.
and
|t+-t-|<4ns
acol<5o
E+>0.75GeV
|E++E-3.686|<0.13GeV

18. Angular distribution
=0.820.17

20. 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
Pmiss<0.18GeV

21. Suppressing +  J/

23. The B(p) has been considered in generator.
Branching ratio of
The B(p) has been considered in generator.

24. PID and second vertex finding are same as above channel.
Pmiss<0.25GeV
N>2
4-C fit,
Determine pair by minizing

26. The B() has been considered in generator.
Branching ratio of
The B() has been considered in generator.

27. 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 combinations can pass the secondary vertex finding algorithm, if more than one, the one with the least will be selected.
Pmiss<0.15GeV

29. The B() has been considered in generator.
Branching ratio of
The B() has been considered in generator.

30. 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 ……

31. Total systematic error
Channel((2S))
(%)
7.1
9.4
13.4
10.3
Results of (2S)BBbar

32. 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

33. Thank you! 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 CLEOc’s. The measured  value in ppbar agrees well with one of theoretical predictions.
Thank you!