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

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

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

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

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

’ 3-body PRD74, 12004 (2006) 921±40 914±42

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

Multi-body ’ decays BESII, PRD73, 052004 (2006)

Multi-body ’ decays BESII, PRD73, 052004 (2006) Some modes are suppressed, some are enhanced, while some others obey the 12% rule!

PRD, 74(072001)

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 ’.

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.

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

Angular distribution =0.820.17

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

Suppressing +  J/

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

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

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

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. Pmiss<0.15GeV

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

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 ……

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

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

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!