measurements of Ψˊ→ vp decays at besii
DESCRIPTION
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. 12-15, 2004, Beijing, China. Introduction. Outline. Introduction PWA of Ψˊ→ π + π - π 0 Study of Ψˊ→ VP - PowerPoint PPT PresentationTRANSCRIPT
MeasurementsMeasurements of of Ψˊ→Ψˊ→VPVP decaydecays at BESIIs at BESII
Zheng Wang
CCAST, Beijing,10039 China
For BES Collaboration.
The 3rd international Quarkonium Working Group (QWG) workshop
Oct. 12-15, 2004, Beijing, China
Outline
Introduction
IHEP Zheng Wang
• Introduction
• PWA of Ψˊ→π+π -π0
• Study of Ψˊ→VP ((,,)(,,ˊ),K*K )• Summary
BES Detector and the data Introduction
IHEP Zheng Wang
0
2
4
6
8
10
12
14
MKI MKII MKIII CBAL BESI BESII CLEOcTracking: Main Drift ChamberPhoton ID: BSCHadron ID: MDC(dE/dx)+TOF
6.42pb-1 continuum data (Ecm=3.65GeV) was used to estimate the continuum bg.
14 Million
From “12% rule” to “ρπ puzzle”
Introduction
IHEP Zheng Wang
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= )ee/J(B)ee)S2((B
)/J())S2((
)ggg/J(B)ggg)S2((B
3s
3s
≈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 }
ρπ Puzzle
Introduction
IHEP Zheng Wang
“12% rule” holds for many exclusive hadronic final state, but violated in Ψ ́→ VP,VT decays compared with the expectation of “12% rule”, the outmost are Ψˊ→ρπ and K*K decays.
Qh values of main J/Ψ and Ψˊhadronic decays in PDG and previous BES results
suppressed
Theoretical explanations
Introduction
IHEP Zheng Wang
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
Theoretical explanations
Introduction
IHEP Zheng Wang
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
PWA of Ψˊ→π+π -π0hep-ex/0408047 submitted to PRL
IHEP Zheng Wang
14M Ψˊdata
2 good tracks , 2 good photons
One π ID.
electron veto(dE/dx & BSC)
µ veto
Kinematic fit (Prob(4C)>0.01)
J/Ψ→μμ decay veto(Mπ+π-<2.95GeV
Mass of π 0 cut
Samples of Ψˊ→π+π-π0
ΨˊData
Continuum Data
Two photons invariant mass
Continuum contributions are subtracted incoherently in 3πevents.
PWA of Ψˊ→π+π -π0
hep-ex/0408047 submitted to PRL
IHEP Zheng Wang
Except the suppression in Ψˊdecay, Dalitz plots for J/Ψand Ψˊ +π -π0 are very different.
ρ(770) band
J/Ψ→μμ decay veto
PWA Ψˊ→ π+π -π0
hep-ex/0408047 submitted to PRL
IHEP Zheng Wang
•ML fit for the Dalitz plot.
•Helicity amplitude:
•ρ and its excited states.
•ρ was described by Gounaris-Sakurai(GS) parameter.
Ψˊ π
πρ
π
PWA of Ψˊ→π+π -π0VP mode
IHEP Zheng Wang
• 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
PWA of Ψˊ→π+π -π0VP mode
IHEP Zheng Wang
Source Relative error(%)
Trigger 0.5
MDC tracking 4.0
Kinematic fit 6.0
Photon efficiency 4.0
Number of photons 2.0
Background estimation 3.6
Particle ID negligible
Total number of Ψˊ 4.0
Continuum subtraction 3.0
Total 10.5
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% & )
Summary of the systematic errors on Br(Ψˊ→π+π-π0).
%0.58 6.10
PWA of Ψˊ→π+π -π0VP mode
IHEP Zheng Wang
Results on BRs_____________________________________________________________________________________________________________________
BR BESII (10 – 5 ) PDG04 (10 – 5 )
Ψˊ + - 0 18.1 1.8 1.9 8 5 Ψˊ 5.1 0.7 0.8 < 8.3 Ψˊ
(2150) + - 0 19.4 2.5________________________________________________
1st measurement or precision much improved.
Interference between ρand its excited states was taken into account.
BE
S P
relimin
ary
Ψˊ→K*(892)K KSK+- +c.c.
hep-ex/0407037 , submitted to PRL
IHEP Zheng Wang
Dalitz plot in ˊK*(892)K KSK
K*
K*0
Ψˊ→K*(892)K
hep-ex/0407037 , submitted to PRL
IHEP Zheng Wang
K* K*09.6±4.2 Evts. 65.6±9.0 Evts.Ψˊ K K* (892)±
Ψˊ→K0 K* (892)0
Br0(15.0±2.1±1.9)10 –5 Br±(2.9±1.3±0.4)10 –5
5.2±2.7 isospin-violation
BE
S P
relimin
ary
Ψˊ→ , 0 ,ˊ,ωη,ωηˊ
IHEP Zheng Wang
VP mode , hep-ex/0408118
Ψˊ→φη
Ψˊ→φπ0 not seen
Ψˊ’( ’ +-, +- )
Ψˊ→ωηΨˊ→ωηˊ
(ηˊ→γππ)
Ψˊ→ωηˊ
(ηˊ→ηππ)
EM Process: 0,,ˊ at Ecm=3650,3686,3773 MeV
EM process, hep-ex/0410031
IHEP Zheng Wang
interference
For EM processes at continuum e+e- (VP) 0 , , ˊ
Pvp(S)=q3vp/3 ; q3
vp – 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 )
BRs (M Ψ(2S) ) & Fvp obtained simultaneously.
EM Process: 0, , ˊ at Ecm=3650, 3686, 3773 MeV
EM process, hep-ex/0410031
IHEP Zheng Wang
Ecm=3650 MeV L = 6.42 pb-1 Ecm=3686 MeV N Ψ(2S) = 14M Ecm=3773 MeVL = 17.3 pb-1
ωπ0
ρη
ρηˊ
0 form factor
VP mode , form factor
IHEP Zheng Wang
Curve A -- J.Gerard, PLB425(1998)365 F(0) ~ 1/s
Curve B –V.Chernyak, hep-ph/9906387 F(0) ~ 1/s2
BE
S P
relimin
ary
Results of Ψˊ→VP
VP mode
’ Nevt B(’) (10-5) B(J/) (10-4)
PDG04
Q (%)
(770) 5.1 0.7 0.8 127 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 15.8 1.6 < 0.7
’ 4.1 2.8 3.1 2.0 0.7 1.67 0.25 26 19
< 3.0 < 0.39 < 0.068
17.8 5.3 3.5 1.0 0.6 6.5 0.7 5.4 1.9
’ 9.1 3.6 3.3 1.3 0.7 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
2.111.25.24.19
BES Preliminary
0.56.42.13
17.078.1 67.0
62.0
2.25.15.2
33.087.1 64.1
11.1
1.56.49.13
28.087.1 68.0
62.0
Test of pQCD 12% Rule
IHEP Zheng Wang
PQCD 12% Rule test using BESII Ψˊ→VP results
12% Rule
Summary
IHEP Zheng Wang
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)Χ10-5 . (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!
BESII .VS. CLEO-cVP mode
Upper limit @90 % C.L.
• 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)
IHEP Zheng Wang
Br(Ψˊ VP) and FVP(S) for 0,,ˊ
VP mode, EM process
IHEP Zheng Wang