1 Lianrong Dai,Beijing MENU 2004, Aug.29-S ep.4,2004 2-Sep-2004 L. R. Dai Department of Physics, Liaoning Normal Universi Z.Y. Zhang, Y.W. Yu Institute of High Energy Physics, Beijing, Chin Nucleon-nucleon interaction in the extended chiral SU(3) quark model
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L. R. Dai (Department of Physics, Liaoning Normal University) Z.Y. Zhang, Y.W. Yu (Institute of High Energy Physics, Beijing, China) Nucleon-nucleon interaction.
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1Lianrong Dai,Beijing MENU 2004, Aug.29-Sep.4,2004 2-Sep-2004
L. R. Dai
(Department of Physics, Liaoning Normal University)
Z.Y. Zhang, Y.W. Yu
(Institute of High Energy Physics, Beijing, China)
Nucleon-nucleon interaction in the extended chiral SU(3)
quark model
Ⅰ:Motivations The chiral SU(3) quark model ‘s success baryon structure’s study on quark level the successful study on nucleon level
Ⅱ:The Model The extended chiral SU(3) quark model Determination of parameters
Ⅲ: Result and discussionⅣ: Summary
Outline
The chiral SU(3) quark model (Nucl.Phys. 625(1997)59)
In this model, the coupling between chiral field and quark is introduced to describe low momentum medium range NPQCD effect. The interacting Lagrangian can be written as:
.
scalar nonet fields pseudo-scalar nonet fields
It is easy to prove that is invariant under the infinitesimal chiral transformation. This can be regarded as an extension of the SU(2) - σ model forstudying the system with s quark.
8 8
I ch a a a a 5a=0 a=0
L = -g ψ( σ λ + i π λ γ )ψ
σ,σ', χ,ε π,K, η, η'
IL L RSU(3) SU(3)
IL
Ⅰ:Motivations
In chiral SU(3) quark model, we still employ an effective OGE
interaction to govern the short range behavior, and a confinement
potential to provide the NPQCD effect in the long distance.
Hamiltonian of the system:
( is taken as quadratic
form.)
i G iji i<j
H = t - T + V ,
,conf ogeij ij i ij
chjV = V + V V+ conf
ijV
ch s(a) ps(a)ij ij ij
a
V = (V + V ) .
1: long range => confinement2: short range =>OGE –color dependent
The expressions of and :
2( )
, ( ), 2 ( ),( ) ( , )12
( ) ( ) ( ) + tensor term
ps ach ps a ps a ij
qi qj
i j a a
mC g m X m r
m m
i j
, ( ), 1 ( ),( ) ( , ) ( ) ( )
term,
ch ps a s a ij a aC g m X m r i j
l s
2
, 2 2( , ) .chC g m m
m
1( , , ) ( ) ( ),X m r Y mr Y rm
32( , , ) ( ) ( ) ( ),X m r Y mr Y r
m
1( ) ,xY x e
x
psijVs
ijV
Here we have only one coupling constant ,chg
s(a)ijV
2chg
4π
ps(a)ijV
2chg
4π
2 2 2ch u NNπ
2N
g m g9= .
4π 25 4πM
spin-flavor dependent
In this chiral SU(3) quark model, in which
short range repulsion is described by OGE
Using the same set of parameters
• Energies of the baryon ground state• NN scattering phase shifts • Hyperon-nucleon (YN) cross sections
can be reproduced reasonably.
* The detailed results have been presentedby Prof.Zhang’s talk today morning!
since last few years, shen et al, Riska and Glozman applied
the quark-chiral field coupling model to study the baryon structure.
Phys. Rev. C55(1997) Phys.Rep.268(1996)263; Nucl.Phys.A663(2000) They have found :
The chiral field coupling is important in explaining the structures of baryons.
As is well known, on baryon level, the
short range repulsion is described successfully by vector meson (ρ,ω, K* and φ) exchanges.
Naturally, we would like to ask which is the
right mechanism for describing the short range interactions ?
1: OGE 2: vector meson exchange 3: or both of them are important