Photoproduction of Photoproduction of K*K* for the for the study of study of (1405)(1405)

Photoproduction of Photoproduction of K*K* for the for the study of study of (1405)(1405)

Tetsuo Hyodoa

a RCNP, Osaka b IFIC, Valencia

2004, January 30th

A. Hosakaa, M. J. Vicente Vacasb and E. Osetb

Special thanks to Prof. Morimatsu

ContentsContents

1. Chiral unitary model1. Motivation : Two poles?2. Framework of the chiral unitary model3. Example : Kp scatterings4. Pole structure of (1405)

2. K*(1405) production1. Advantage of the reaction2. Effective interactions3. Numerical results4. Summary and conclusions

Motivation : Two poles?Motivation : Two poles?

• 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, 025203 T. Hyodo et al. PRC68, 018201

There are two poles of the scattering amplitudearound nominal (1405) energy region.

(1405) : JP=1/2, I=0

ChU model, T. Hyodo

Chiral unitary modelChiral unitary model

Unitarity of S-matrixChiral symmetry

Flavor SU(3) meson-baryon scatterings (s-wave)

Resonances

Low energy behavior

Non-perturbativeresummation

(1405), (1670), N(1535),(1620), (1620)

Dynamicalgeneration

Chiral perturbation theory

Unitarization

Framework of the chiral unitary modelFramework of the chiral unitary model

Resonances

Generated resonances areexpressed as poles of the scattering amplitude.

Total cross sections of Kp scatteringsTotal cross sections of Kp scatterings

T. Hyodo, et al., Phys. Rev. C 68, 018201 (2003)

200

150

100

50

0300200100

K-p

70

60

50

40

30

20

10

0300200100

π0

200

150

100

50

0300200100

π+−

60

50

40

30

20

10

0300200100

Plab [ / ]MeV c

K0n

60

50

40

30

20

10

0300200100

Plab [ / ]MeV c

π0080

60

40

20

0300200100

Plab [ / ]MeV c

π−+

Poles of amplitude in S=1 channelPoles of amplitude in S=1 channel

D. Jido, et al., Nucl. Phys. A 723, 205 (2003)

8×8 ~ 1,8,8,10,10,27attractive repulsive

(1405) in the chiral unitary model(1405) in the chiral unitary model

D. Jido, et al., Nucl. Phys. A 723, 205 (2003)

π mass distribution

1390 + 66i (π

1426 + 16i (KN)

Photoproduction of K* (1405)Photoproduction of K* (1405)

Only Kp channel appears at the initial stage

Higher pole ??

Advantage of this reactionAdvantage of this reaction

With polarized photon beam, the exchangedparticle can be identified.

Clear mechanism

Effective interactions for vector mesonEffective interactions for vector meson

1. VP coupling

2. VPP coupling

3. (1385)MB coupling

4. Form factor

Effective interaction for baryon resonanceEffective interaction for baryon resonance

ChU amplitude

(1385) pole term

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0300028002600240022002000

[ ]s MeV

π00 ( =0)I π+-

π-+

π0 ( =1)I

(1405)*KKππ

Total cross sectionTotal cross section

4

3

2

1

015001450140013501300

MI [ ]MeV

π00 ( =0)I π+-

π-+

π0 ( =1)I

nvariant mass distributionnvariant mass distribution

Plab = 2.5 GeV/csqrt s ~ 2.35 GeV

Isospin decomposition of π statesIsospin decomposition of π states

• Difference among charged states -> when summed up, this term vanishes

• No p-wave contribution -> I=1 s-wave amplitude

4

3

2

1

015001450140013501300

MI [ ]MeV

π00 ( =0)I π+-

π-+

π0 ( =1)I

( π+- + π-+ ) / 2

nvariant mass distribution 2nvariant mass distribution 2

Plab = 2.5 GeV/csqrt s ~ 2.35 GeV

I=1, s-wave amplitdueI=1, s-wave amplitdue

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

15001450140013501300MI [ ]MeV

π+- − π-+

π ( =1)I

Summary and conclusions 1Summary and conclusions 1

We study the structure of (1405) using the chiral unitary model.

� There are two poles of the scattering amplitude around nominal (1405).

Pole 1 (1426+16i) : strongly couples to KN statePole 2 (1390+66i) : strongly couples to π state

� By observing the charged π states in the p -> K*(1405) reaction, it is possible to isolate higher energy pole.

Summary and conclusions 2Summary and conclusions 2

� If we observe neutral π state, clear I=0 distribution is obtained.

� Combining three π states, we can also study the s-wave I=1 amplitude, where the existence of another pole is argued.

T. Hyodo, et al, nucl-th/0401051

http://www.rcnp.osaka-u.ac.jp/~hyodo/

Appendix : other processesAppendix : other processes

p -> Kπ

p -> πJ.C. Nacher, et al., PLB461, 299(1999)

J.C. Nacher, et al., PLB445, 55(1999)