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Some Theoretical Issues of Hadron Productions and Properties from J/ Decays. Shen Pengnian Institute of High Energy Physics (IHEP) Chinese Academy of Sciences [email protected]. Aug.30-Sept.4,2004 MENU’04. Introduction Baryon and its Excited States in J/ Decay - PowerPoint PPT Presentation
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Some Theoretical Issues of
Hadron Productions and Properties
from J/ Decays
Shen PengnianInstitute of High Energy Physics (IHEP)
Chinese Academy of Sciences
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