1. Photoproduction of K* for the study of the structure of L(1405)
Tetsuo Hyodoa
A. Hosakaa, E. Osetb, A. Ramosc and M. J. Vicente Vacasb
a RCNP, Osaka b IFIC, Valencia c Barcelona Univ.
2003, November 4th

2. Chiral unitary model K*L(1405) production Introduction
Contents
Introduction
Motivation : Two poles?
Chiral unitary model
Framework of the chiral unitary model
Example : K-p scatterings
Pole structure of L(1405)
Example : p-p -> K0pS
K*L(1405) production
Effective interactions
Numerical results

3. L(1405) : JP=1/2-, I=0 Motivations : Two poles?
There are two poles of the scattering amplitude
around nominal L(1405) energy region.
Cloudy bag model
(1990)
J. Fink et al. PRC41, 2720
Chiral unitary model
(2001~)
J. A. Oller et al. PLB500, 263
E. Oset et al. PLB527, 99
D. Jido et al. PRC66,
T. Hyodo et al. PRC68,
L(1405) : JP=1/2-, I=0
ChU model, T. Hyodo

4. Low energy behavior Non-perturbative resummation
Chiral unitary model
Flavor SU(3) meson-baryon scatterings (s-wave)
Chiral symmetry
Unitarity of S-matrix
Low energy
behavior
Non-perturbative
resummation
Dynamical
generation
Resonances
L(1405), L(1670), N(1535),
S(1620), X(1620)

5. Chiral perturbation theory
Framework of the chiral unitary model
Chiral perturbation theory
Unitarization
Generated resonances are
expressed as poles of the
scattering amplitude.
Resonances

6. Total cross sections of K-p scatterings
T. Hyodo, et al., Phys. Rev. C 68, (2003)

7. L(1405) in the chiral unitary model
pS mass distribution
i (pS)
i (KN)
D. Jido, et al., Nucl. Phys. A 723, 205 (2003)

8. Example : the p-p -> K0pS reaction
Chiral unitary model
Chiral
term
N(1710)

9. There are two mechanisms in the initial
Results for p-p -> K0pS
Mass distribution
Total cross sections [mb]
S(1385) effect
Good agreement
There are two mechanisms in the initial
stage interaction, which filter each one
of the resonances.
T. Hyodo, et al., nucl-th/ , Phys. Rev. C, in press

10. Higher pole ?? Only K-p channel appears at the initial stage
Photoproduction of K* L(1405)
Only K-p channel appears at the initial stage
Higher pole ??

11. Effective interactions for meson part
gVP coupling
VPP coupling

12. Effective interaction for S(1385)
S(1385)MB coupling
K-P -> S(1385) -> MB amplitude
SU(6) symmetry

13. Experiments : pS mass distribution
Plab = 2.5 GeV/c
sqrt s ~ 2.35 GeV
Preliminary

14. We study the structure of L(1405) using the chiral unitary model.
Summary and conclusions
We study the structure of L(1405) using
the chiral unitary model.
There are two poles of the scattering
amplitude around nominal L(1405).
Pole 1 ( i) : strongly couples to KN state
Pole 2 ( i) : strongly couples to pS state
By observing the pS mass distribution in
the gp -> K*L(1405) reaction, it could be
possible to isolate higher energy pole.

15. gp -> K-pS K-p -> gpS Spring-8 J-PARC?
Appendix : other processes
gp -> K-pS
J.C. Nacher, et al., PLB445, 55(1999)
Spring-8
K-p -> gpS
J.C. Nacher, et al., PLB461, 299(1999)
J-PARC?