1. Measurements of Ψˊ→VP decays at BESII
Zheng Wang
CCAST, Beijing,10039 China
For BES Collaboration.
The 3rd international Quarkonium Working Group (QWG) workshop
Oct , 2004, Beijing, China

2. Outline Introduction PWA of Ψˊ→π+π-π0 Study of Ψˊ→VP
((,,)(,,ˊ),K*K )
Summary
IHEP Zheng Wang

3. BES Detector and the data
Introduction
BES Detector and the data
14 Million
Tracking: Main Drift Chamber
Photon ID: BSC
6.42pb-1 continuum data (Ecm=3.65GeV) was used to estimate the continuum bg.
Hadron ID: MDC(dE/dx)+TOF
IHEP Zheng Wang

4. From “12% rule” to “ρπ puzzle”
Introduction
From “12% rule” to “ρπ puzzle”
J/ and ’ hadronic decays proceed via 3 gluons or a virtual photon, neglect the difference of S at J/ and ’ , the ratio of ’ and J/ BRs is :
Qh=
≈12%
Suppression in VP mode ( & K*K ) revealed by MARK-II
{ M.E.B. Franklin et al, PRL 51 (1983) 963 }
Suppression confirmed by BESI with higher sensetivity
{ Y.S.Zhu, Proc. of ichep ‘96, p.507 }
IHEP Zheng Wang

5. Introduction
ρπ Puzzle
suppressed
Qh values of main J/Ψ and Ψˊhadronic decays in PDG and previous BES results
“12% rule” holds for many exclusive hadronic final state, but violated in Ψˊ → VP,VT decays compared with the expectation of “12% rule”, the outmost are Ψˊ→ρπ and K*K decays.
IHEP Zheng Wang

6. Theoretical explanations
Introduction
Theoretical explanations
Brodsky, Lepage, Tuan: { PRL 59 (1987) 621 }
Intermediate vector glueball
Chaichian & Torngvist : { NP B323 (1989) 75 }
Hadronic form factor
Pinsky : { PL B236 (1990) 479 }
Generalized hindered M1 transition
Li-Bugg-Zou { PR D55 (1997) 1421 }
Final-state interaction
Brodsky-Karliner { PRL 78 (1997) 4682 }
Intrinsic charm |qqcc> Fock components
of the light vector mesons
Chen-Braaten { PRL 80 (1998) 5060 }
Fock state with cc pair in a color-octet
IHEP Zheng Wang

7. Theoretical explanations
Introduction
Theoretical explanations
Gerard-Weyers { PL B462 (1999) 324 }
cc annihilation into 5g via 2 steps
Feldmann-Kroll { PR D62 (2000) }
Decays thru light-quark Fock component
by a soft mechanism
Suzuki { PR D63 (2001) }
(2S) - vector glueball mixing
Rosner { PR D64 (2001) }
(2S) - (1D) mixing
J. P. Ma { PR D65 (2002) }
Relativistic Correction
IHEP Zheng Wang

8. PWA of Ψˊ→π+π-π0 ΨˊData Continuum Data Two photons invariant mass
hep-ex/ submitted to PRL
PWA of Ψˊ→π+π-π0
14M Ψˊdata
ΨˊData
2 good tracks，2 good photons
One π ID.
electron veto(dE/dx & BSC)
µ veto
Continuum Data
Kinematic fit (Prob(4C)>0.01)
J/Ψ→μμ decay veto(Mπ+π-<2.95GeV
Two photons invariant mass
Mass of π0 cut
Continuum contributions are subtracted incoherently in 3πevents.
Samples of Ψˊ→π+π-π0
IHEP Zheng Wang

9. hep-ex/0408047 submitted to PRL
PWA of Ψˊ→π+π-π0
ρ(770) band
J/Ψ→μμ decay veto
Except the suppression in Ψˊdecay, Dalitz plots for J/Ψand Ψˊ  +π-π0 are very different.
IHEP Zheng Wang

10. hep-ex/0408047 submitted to PRL
PWA Ψˊ→ π+π-π0
ML fit for the Dalitz plot.
Helicity amplitude:
ρ and its excited states.
ρ was described by Gounaris-Sakurai(GS) parameter. Ψˊ π ρ π π
IHEP Zheng Wang

11. PWA of Ψˊ→π+π-π0 in Ψˊ→3π process. (770)π, (2150)π are dominant.
VP mode
PWA of Ψˊ→π+π-π0
Ψˊ→ρ(770)π decay mode is observed for the first time.
in Ψˊ→3π process. (770)π, (2150)π are dominant.
3π: (770)π: (2150) π
= 1:0.28±0.03:1.07±0.09
IHEP Zheng Wang

12. Summary of the systematic errors on Br(Ψˊ→π+π-π0).
VP mode
PWA of Ψˊ→π+π-π0
Source
Relative error(%)
Trigger
0.5
MDC tracking
4.0
Kinematic fit
6.0
Photon efficiency
Number of photons
2.0
Background estimation
3.6
Particle ID
negligible
Total number of Ψˊ
Continuum subtraction
3.0
Total
10.5
Summary of the systematic errors on Br(Ψˊ→π+π-π0).
For the ρ(770)π and ρ(2150)π the uncertainties of fitting with different high mass ρ sates and different background shapes are also included. (16.0% & )
IHEP Zheng Wang

13. ________________________________________________
VP mode
PWA of Ψˊ→π+π-π0
Results on BRs
_____________________________________________________________________________________________________________________
BR BESII (10 – 5 ) PDG04 (10 – 5 )
Ψˊ + -   1.8   5
Ψˊ    0.7  < 8.3
Ψˊ
(2150)   + -   2.5
________________________________________________
1st measurement or precision much improved.
Interference between ρand its excited states was taken into account.
BES Preliminary
IHEP Zheng Wang

14. hep-ex/0407037 , submitted to PRL
Ψˊ→K*(892)K KSK+- +c.c.
K*
K*0
Dalitz plot in  ˊK*(892)K  KSK
IHEP Zheng Wang

15. hep-ex/0407037 , submitted to PRL
Ψˊ→K*(892)K
K*
9.6±4.2 Evts.
K*0
65.6±9.0 Evts.
BES Preliminary
Ψˊ K K* (892)±
Ψˊ→K0 K* (892)0
Br±(2.9±1.3±0.4)10 –5
Br0(15.0±2.1±1.9)10 –5
5.2±2.7
isospin-violation
IHEP Zheng Wang

16. Ψˊ→ , 0 ,ˊ,ωη,ωηˊ VP mode , hep-ex/0408118 Ψˊ→ωη IHEP Zheng Wang
Ψˊ→φη
Ψˊ→φπ0 not seen
Ψˊ’
( ’ +-, +- )
Ψˊ→ωηˊ
(ηˊ→γππ)
Ψˊ→ωηˊ
(ηˊ→ηππ)
Ψˊ→ωη
IHEP Zheng Wang

17. EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV
EM process, hep-ex/
EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV
For EM processes at continuum e+e-  (VP) 0 , , ˊ
Pvp(S)=q3vp/ ; q3vp – momentum of V or P ;
Fvp(s) – form factor .
For EM processes at Ψˊ  (VP) 0, , ’
=R+cont (INT  0, P.Wang et al, PL B593 (2004) 89 )
interference
BRs (M Ψ(2S) ) & Fvp obtained simultaneously.
IHEP Zheng Wang

18. EM Process: 0, , ˊ at Ecm=3650, 3686, 3773 MeV
EM process, hep-ex/
EM Process: 0, , ˊ at Ecm=3650, 3686, 3773 MeV
ωπ0 ρη
ρηˊ
Ecm=3650 MeV L = 6.42 pb-1
Ecm=3686 MeV N Ψ(2S) = 14M
Ecm=3773 MeVL = 17.3 pb-1
IHEP Zheng Wang

19. 0 form factor BES Preliminary Curve A -- J.Gerard, PLB425(1998)365
VP mode , form factor
0 form factor
BES Preliminary
Curve A -- J.Gerard,
PLB425(1998)365
F(0) ~ 1/s
Curve B –V.Chernyak,
hep-ph/
F(0) ~ 1/s2
IHEP Zheng Wang

20. Results of Ψˊ→VP VP mode BES Preliminary ’ Nevt B(’) (10-5)
B(J/) (10-4)
PDG04
Q (%)
 (770) 
5.1   0.8
 9
0.40 0.08
 (2150) 
 
1.93  0.23
9.2  3.7
 ’
1.05  0.18
17.8  12.9
 
4.2  0.6
4.5  1.8
 
<4.3
< 1.6
 1.6
< 0.7
 ’
4.1 2.8
3.1   0.7
1.67  0.25
26  19
 
< 3.0
< 0.39
<
 
17.8  5.3
3.5   0.6
6.5  0.7
5.4  1.9
 ’
9.1  3.6
3.3   0.7
3.3  0.4
9.7  4.5
K+K*-+c.c.
9.6  4.2
2.9   0.4
50  4
0.58  0.27
K0K*0+c.c.
65.6  9.0
  1.9
42  4
3.6  0.8
BES Preliminary

21. PQCD 12% Rule test using BESII Ψˊ→VP results
Test of pQCD 12% Rule
12% Rule
PQCD 12% Rule test using BESII Ψˊ→VP results
IHEP Zheng Wang

22. Summary Thanks ! 谢谢！ Measured BRs or upper limits of VP channels:
ˊ (,,)(,,’), K*K (12 channels)
In ˊ +π-π0, (770)π decay was observed for the first time. Br(Ψˊ  )= (5.1  0.7  0.8)Χ (770) & (2150) dominant.
Observe large isospin-violation in ˊ K*K channel.
F(0,,ˊ) at Ecm=3650, 3686, 3773 MeV measured.
Tested 12% rule for all these decay modes. Some suppressed, some consistent. 12% rule seems to be too simplistic. A theory which can quantitatively describe these data is desired. More and accurate J/ ,ˊ and continuum data are helpful to elucidate the J/ and ˊ properties as well as properties of strong interaction.
Thanks ! 谢谢！
IHEP Zheng Wang

23. BESII .VS. CLEO-c Most channels BRs are consistent. BES BR()>CLEO
VP mode
BESII .VS. CLEO-c
Most channels BRs are consistent.
BES BR()>CLEO
by ~ 3 because the different treatment of continuum BG. and the interference between ρ(770) and its excited state in PWA.
BR(K*0K0) are deviated (different treatment of the continuum contribution)
Upper C.L.
IHEP Zheng Wang

24. Br(Ψˊ  VP) and FVP(S) for 0,,ˊ
VP mode, EM process
Br(Ψˊ  VP) and FVP(S) for 0,,ˊ
IHEP Zheng Wang