Download 756KB

Resonances in Ψˊ→π+π-π0 and
study of Ψˊ→VP decays at BESII
Zheng Wang
IHEP, Beijing,10039 China
For BES Collaboration.
Topical Seminar on Frontier of Particle physics 2004: QCD and Light Hadrons
Sep. 26-30, 2004, Beijing, China
Introduction
Outline
• Introduction
• PWA of Ψˊ→π+π-π0
• Study of Ψˊ→VP
((,,)(,,ˊ),K*K )
• Summary
IHEP
Zheng Wang
Introduction
BES Detector and the data
14
14 Million
12
10
8
6
4
2
0
Tracking: Main Drift Chamber
Photon ID: BSC
Hadron ID: MDC(dE/dx)+TOF
IHEP
Zheng Wang
MKI
MKII
MKIII CBAL BESI
BESII CLEOc
6.42pb-1 continuum data
(Ecm=3.65GeV) was used to
estimate the continuum bg.
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 :
B( (2S)  ggg )  3s ( (2S)) B( (2S)  e  e  )
Qh= B(J /  ggg )   3 (J / ) B(J /  e e ) ≈12%
s
•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
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
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
Introduction
Theoretical explanations
Gerard-Weyers
{ PL B462 (1999) 324 }
cc annihilation into 5g via 2 steps
Feldmann-Kroll
{ PR D62 (2000) 074006 }
Decays thru light-quark Fock component
by a soft mechanism
Suzuki
{ PR D63 (2001) 054021 }
(2S) - vector glueball mixing
Rosner
{ PR D64 (2001) 094002 }
(2S) - (1D) mixing
J. P. Ma
{ PR D65 (2002) 097506 }
Relativistic Correction
IHEP
Zheng Wang
hep-ex/0408047 submitted to PRL
PWA of Ψˊ→π+π-π0
14M Ψˊdata
ΨˊData
2 good track，2 more good gamma
One π ID.
electron veto
µ veto
Continuum Data
Kinematic fit
J/Ψ→μμ decay veto
Mass of π0 cut
Samples of Ψˊ→π+π-π0
IHEP
Two photons invariant mass
Continuum contribution are subtracted
incoherently in 3 πevents.
Zheng Wang
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
hep-ex/0408047 submitted to PRL
PWA Ψˊ→ π+π-π0
•ML fit for the Dalitz plot.
π
Ψˊ
ρ
•Helicity amplitude:
π
π
•ρ and its excited states.
•ρ was described by Gounaris-Sakurai(GS) parameter.
IHEP
Zheng Wang
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
VP mode
PWA of Ψˊ→3π
Results on BRs
_____________________________________________________________________________________________________________________
Ψˊ + - 0
18.1  1.8  1.9
Ψˊ  
5.1  0.7  0.8
PDG04 (10 – 5 )
8  5
< 8.3
Ψˊ
(2150)   + - 0
19.4  2.5
________________________________________________

1st measurement or precision much improved.
BES Preliminary
BESII (10 – 5 )
BR
Interference between ρand its excited states was taken
into account.

IHEP
Zheng Wang
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
hep-ex/0407037 , submitted to PRL
Ψˊ→K*(892)K
K*
9.6±4.2 Evts.
K*0 65.6±9.0 Evts.

Br±(2.9±1.3±0.4)10 –5
5.2±2.7
IHEP
Zheng Wang
Ψˊ→K0 K* (892)0
Br0(15.0±2.1±1.9)10 –5
isospin-violation
BES Preliminary
Ψˊ K K* (892)±
VP model
Ψˊ→ , 0 ,ˊ,ωη,ωηˊ
Ψˊ’
( ’ +-, +- )
Ψˊ→φη
Ψ→φπ0 not
seen
Ψˊ→ωη
IHEP
Ψˊ→ωηˊ
Ψˊ→ωηˊ
(ηˊ→γππ)
(ηˊ→ηππ)
Zheng Wang
VP mode, EM process
EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV
For EM processes at continuum e+e-  (VP) 0 , , ˊ
Pvp(S)=q3vp/3
; 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
VP model ,EM process
EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV
ωπ0
ρη
ρηˊ
Ecm=3650 MeV L = 6.42 pb-1
IHEP
Ecm=3686 MeV N Ψ(2S) = 14M
Zheng Wang
Ecm=3773 MeVL = 17.3 pb-1
VP mode ,form factor
0 form factor
Curve B –V.Chernyak,
hep-ph/9906387
F(0) ~ 1/s2
IHEP
Zheng Wang
BES Preliminary
Curve A -- J.Gerard,
PLB425(1998)365
F(0) ~ 1/s
VP model
Results of Ψˊ→VP
’
Nevt
 (770) 
B(’)
(10-5)
5.1  0.7  0.8
 (2150) 
B(J/) (10-4)
PDG04
127
9
Q (%)
0.40 0.08
.2
19.4  2.5 11
2.1

13.2  4.8
1.78  0.65  0.22
1.93  0.23
9.2  3.7
 ’
2.5  1.7
1.87  1.27  0.36
1.05  0.18
17.8  12.9

14.0 4.8
1.88  0.64  0.32
4.2  0.6
4.5  1.8

<3.3
< 1.1
 ’
4.1 2.8
4.3  2.9  1.0
1.67  0.25

< 3.0
< 0.3
< 0.068

17.8  5.3
3.5  1.0  0.6
6.5  0.7
5.4  1.9
 ’
9.1  3.6
3.2  1.3  0.6
3.3  0.4
9.7  4.5
K+K*-+c.c.
9.6  4.2
2.9  1.3  0.4
50
4
0.58  0.27
K0K*0+c.c.
65.6  9.0
15.0  2.1  1.9
42
4
3.6  0.8
15.8  1.6
< 0.7
26  19
BES Preliminary
Test of pQCD 12% Rule
PQCD 12% Rule test using BESII Ψˊ→VP results
IHEP
Zheng Wang
Summary
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. (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 !
IHEP
Zheng Wang
谢谢！
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
Upper limit @90％ C.L.
IHEP
Zheng Wang
VP mode, EM process
Br(Ψˊ  VP) and FVP(S) for 0,,ˊ
IHEP
Zheng Wang
,ˊ at Ecm=3650,3686,3773 MeV
e+e-   at
Ecm=3650MeV
Ψˊ 
e+e-  ’ at
Ecm=3650MeV
Ψˊ  ’
IHEP
Zheng Wang
e+e-   at
Ecm=3773 MeV
e+e-  ’ at
Ecm=3773 MeV