Some Theoretical Issues of

Hadron Productions and Properties

from J/ Decays

Shen PengnianInstitute of High Energy Physics (IHEP)

Chinese Academy of Sciences

shenpn@mail.ihep.ac.cn

Aug.30-Sept.4,2004

MENU’04

Collaborators: IHEP: H.C.Chiang, B.S.Zou, Z.Y.Zhang, R.G.Ping, W.H.Liang, F.K.Guo, Z.Q.Zeng, H.M.Zhao GSCAS: Y.B.Ding Nankai U.: X.Q.Li

Introduction Baryon and its Excited States in J/ Decay Multiquark Systems in J/, Decays Remarks

- Multiquark states

- Meson

- Baryon

Hadron: smallest directly observed particle

Introduction

• Structure

• Interaction: QCD theory

NPQCD models

- Potential model

- Bag model

- Lattice calculation

- QCDSR, QFT

...

• experimental data of Spectrum

Decay property

base of model theory

• some unsolved problems

- missing baryon excited state

structure

interactionDifferent interaction energy

Different Spectrum

Decay property

Prog. Part. Nucl. Phys. 45 (2000) S241

- Existence of multiquark states

• Need further experimental and

theoretical investigations

- Roper resonance

3q?

3q-g?

5q?

Baryon and its excited state studies in J/ decay

• N* production via J/ decay

W.H.Liang et al., J.Phys.G28(2002)333

B.S.Zou et al., Phys.Rev.C67(2003)015204

N* production processes

electro- and photo-production

J/ hadronic decay

advantages of N* production through J/ decay

simple isospin structure

easily study N* that couples to

,,,', KNNNN

simultaneously study N*(3q) and N*(3q-g)

can study lower lying *, *, *

covariant tensor PWA for decay data analysis

effective vertices involved should satisfy

Lorentz invariant

CPT invariant

C invariant

P invariant

W.H.Liang et al., nucl-th/0404024

background analysis N-pole contribution

in case

coupling vertex

PS:

PV:

coupling vertex

experimental data:

calculated results: take |F0|/|FM|=0.12

PS:

PV:

branching ratio for

without form factor

with form factor

frequently used form factors

branching ratio for

Take frequently used form factors

[1] C.Schütz et al., Phys.Rev.C49(1994)2671

[2] B.C.Pearce et al., Nucl.Phys.A528(1991)655

[3]Y.Oh et al., Phys.Rev.C63(2001)25201

N-pole contribution is about 5~20% of data

for

experimental data

calculated result

without F.F.

with F.F.

N-pole contribution is <1% of data

NN coupling vertices

vector

tensor

In case

with F.F.

without F.F.

branching ratio

N-pole contribution is about 5~10% of data

experimental data

calculated result ( )

W.H.Liang, Ph.D. thesis, (2002)

• application of J/ decay in baryon

model study

extract vertex information from RCQM

decay amplitude in hilicity frame

decay amplitude in covariant tensor analysis

extract vertex information from GBE

Vertices in GBE

Vertices in covariant tensor analysis

† vertex coupling parameters are extracted from S.Capstick et al., Phys.Rev.D49(1994)4570

Phys.Rev.D46(1992)2864

†† vertex coupling parameters are extracted from D.O.Riska et al., Nucl Phys.A663-664(2000)103

take and missing state

that strongly couple to N decay channel† into account

RCQM

GBE

0

Cos()

0

Cos()

calculation in

• J/ Decay for Structure Study of Baryon

and its excited state R.G.Ping et al., Phys.Rev. D66(2002)054020,

Chin.Phys.Lett.19(2002)1592,nucl-th/0408007

some microscopic diagrams

assume

hadronization can approximately be considered by taking quark model wave function of baryon

and can be treated by perturbative QCD

study

using (uds) basis and considering Lorentz boost

At least ground states of baryon can be well described bysimply quark model

study gI through and

N*(1440) structure (w.f.)

3q:

3q-g:

3q- (3q-g):

Parameter setting

numerical results

Further data distinguish structure of Roper

Possible Multiquark Systems in J/, ’, decays

production way

direct production

dynamic production

6q system?

experiment data of

J.Z.Bai et al., BES Collaboration, Phys.Rev.Lett. 91(2003)022001

S-wave Breit-Wigner fit

P-wave Breit-Wigner fit

Some recent theoretical discussions

final state interaction: ( B.S.Zou,et al., Phys.Rev.D69(2004)034004)

FSI ?

can be explained by interaction gained from LEAR (B.Kerbikov et al., Phys.Rev.C69(2004)055205)

Toy model: ( D.Alakabha et al., Phys.Lett.B567 (2003)273)

Skyrme model: ( M.L.Yan,et al., hep-ph/0405087)

linear model: ( X.Liu,et al., hep-ph/0406118)

constituent quark model: ( C.H.Chang,et al., hep-ph/0405087)

bound state or a resonant state ?

Paris potential:

M.Pignone,et al., Phys.Rev.C50(1994)2710

Z.Q.Zeng et al., manuscript

no S-wave bound state or resonant state

no S-wave bound state or resonant state

M.Ablikim et al., BES Collaboration, hep-ex/0405050

experiment data of

S-wave Breit-Wigner fit

Some recent theoretical discussions

Symmetry analysis

In is possible a

or state

X.G.He et al., hep-ph/0407083

experimental data of

and

M.Ablikim et al., BES Collaboration, hep-ex/0402012

No significant (1540) signal

5q system?

4q system?

heavy quarkonium transitions

suggest a new mechanism

X might be a quark state

This 4 quark state was also suggested by V. Anisovich et al., Phys.Rev.D51(1995)R4619

further study on q-g degrees of freedom is needed

Conclusion

• N* spectrum can provide information of baryon inner structure and NPQCD effect of strong interaction

• J/ decay can produce N* for baryon spectrum study

• Possible to produce multiquark states via J/, ’, decay, further study on q-q DOF is needed

Thank you