1. 5-quark states in a chiral potential Atsushi Hosaka (RCNP)
Structure of a Pentaquark baryon Q +
JPS meeting Miyazaki, Sept 2003

2. Experiment at LEPS Quantum numbers
JPS meeting Miyazaki, Sept 2003
Experiment at LEPS
Quantum numbers
At least 4 quarks + 1 antiquark => Purely exotic
Quark content =>
Unknoswn quantum numbers

3. Theta production at LEPS

4. JPS meeting Miyazaki, Sept 2003
picture

5. JPS meeting Miyazaki, Sept 2003
Quark model
Flavor structure

6. Masses Parity Sum of constituent quarks udud s Negative
JPS meeting Miyazaki, Sept 2003
Masses
Parity
Sum of constituent quarks p
udud s
Negative

7. KN Bound state approach of Skyrmion
JPS meeting Miyazaki, Sept 2003
KN Bound state approach of Skyrmion
S-wave bound state => Negative parity
P-wave bound state => Positive parity
P-orbit P s

8. Chiral soliton Assumptions: • Large-Nc => Skyrme soliton (hedgehog)
JPS meeting Miyazaki, Sept 2003
Chiral soliton
Diakonov et al (1997)
Assumptions:
• Large-Nc => Skyrme soliton (hedgehog)
• SU(3) collective motion in flavor space
Rotation of a hedgehog in
SU(3) flavor space

9. Predictions Spin parity JP = 1/2+ Flavor 10, Isospin I = 0
JPS meeting Miyazaki, Sept 2003
Predictions
Flavor 10, Isospin I = 0
Relatively small M(Q+)
Wider splitting
Spin parity JP = 1/2+
and small width ~ 15 MeV

10. Chiral popential Chiral bag model Hedgehog Chiral MIT
JPS meeting Miyazaki, Sept 2003
Chiral popential
Chiral bag model
Hosaka Toki, Phys Rep ‘96
Hedgehog
MIT
Chiral
Grand angular momentum

11. s-t interaction Hedgehog corraltion Spin-isospin splitting
JPS meeting Miyazaki, Sept 2003
s-t interaction
Hedgehog corraltion
Spin-isospin splitting

12. Chiral bag Positive parity Negative parity
JPS meeting Miyazaki, Sept 2003
Chiral bag
Negative parity
Positive parity

13. Theory and exp Const. quark model Chiral soliton: Collective quant.
Skyrmion bound state
Chiral bag
Diquark
Sum rule
Lattice
Gamma + n, p, d ->
K+ + n, p, d ->
pp ->

14. What more? Spin and parity 2. Internal structure of 5quarks
JPS meeting Miyazaki, Sept 2003
What more?
Spin and parity
2. Internal structure of 5quarks
Diquark correlation
Chiral interaction
Other bound states of many quarks
(2)
(1)
polarization
total cross sections