Measurements of Ψˊ→ VP decays at BESII

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