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K*Λ(1116) Photoproduction and Nucleon resonances Sang-Ho Kim( 金金金 ) (NTG, Inha University, Korea) In collaboration with Hyun-Chul Kim (Inha University), Yong-Seok Oh (Kyungpook National University), Seung-il Nam (Korea Aerospace University) BARYONS’2010,7-11 Dec, Osaka, Japan

K*Λ(1116) Photoproduction and Nucleon resonances

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BARYONS’2010,7-11 Dec, Osaka, Japan. K*Λ(1116) Photoproduction and Nucleon resonances. Sang-Ho Kim( 金相鎬 ) (NTG, Inha University, Korea). In collaboration with Hyun-Chul Kim (Inha University), Yong-Seok Oh (Kyungpook National University), - PowerPoint PPT Presentation

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Page 1: K*Λ(1116) Photoproduction  and Nucleon resonances

K*Λ(1116) Photoproduction and

Nucleon resonances

K*Λ(1116) Photoproduction and

Nucleon resonances

Sang-Ho Kim( 金相鎬 ) (NTG, Inha University, Korea)

In collaboration with Hyun-Chul Kim (Inha University), Yong-Seok Oh (Kyungpook National University), Seung-il Nam (Korea Aerospace University)

BARYONS’2010,7-11 Dec, Osaka, Japan

Page 2: K*Λ(1116) Photoproduction  and Nucleon resonances

1. Introduction & Motivation

2. Theoretical framework ※ Tree-level Born approximation ※ Effective Lagrangian ※ Amplitude and Form factor 3. Numerical results 4. Conclusion

5. Outlook

Outline

Page 3: K*Λ(1116) Photoproduction  and Nucleon resonances

1. Introduction

◈ It has been a very useful experimental tool to investigate QCD as a hadronic degrees of freedom.

◈ In theoretical sides, there have been various tools developed to investigate the photoproductions.

◈ Around the world, there are many experimental facilities and collaborations for this purpose, such as the CLAS at JLAB, LEPS at SPring-8, Bonn-ELSA, Tohoku LNS, etc.

The meson photoproduction off the nucleon targetThe meson photoproduction off the nucleon target

Page 4: K*Λ(1116) Photoproduction  and Nucleon resonances

1. Motivation

Although the K* production rate is smaller than that for the K, it is still sizable.

L. Guo et al. [CLAS collaboration], hep-ex/0601010

Page 5: K*Λ(1116) Photoproduction  and Nucleon resonances

1. Motivation

◈ It would be a right subject to study the heavy mass hadron productions, according to the recent experimental progesses.

◈ Nucleon resonances in strangeness production will give more information on microscopic hadron studies.

◈ It is interesting to study additional polarization observables together with the photon, target nucleon, and K* polarizations (future works).

◈ Since we do not have much experimental data for this channel, it would be a highly prospective subject for the possible future experiments.

Vector strangeness meson, K* photoproduction Vector strangeness meson, K* photoproduction

Page 6: K*Λ(1116) Photoproduction  and Nucleon resonances

2. Theoretical framework

◆ ◆ Effective Lagrangians for interaction vertices.

◆ ◆ Born approximation at tree level.

◆ ◆ Gauge invariant form factor prescription.

◆ ◆ Nucleon resonances in a full relativistic way.

Page 7: K*Λ(1116) Photoproduction  and Nucleon resonances

Tree diagrams

2. Born approximation

Page 8: K*Λ(1116) Photoproduction  and Nucleon resonances

2. Effective Lagrangiant-channel

K* exchange

K exchange

κ exchange

Page 9: K*Λ(1116) Photoproduction  and Nucleon resonances

2. Effective Lagrangianu-channel and contact term

● This contact diagram is essential to satisfy the gauge-invariance condition.

Page 10: K*Λ(1116) Photoproduction  and Nucleon resonances

2. Effective Lagrangians-channel

Page 11: K*Λ(1116) Photoproduction  and Nucleon resonances

2. Amplitude and Form factor

t-channel

s-, u-channel

Amplitude

Form factor

common form factor

Page 12: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Total Cross section

K-meson exchange dominates

remarkably.

There is considerable discrepancy

between the theory and experiment.

Therefore, to cure the problem, we

are motivated to include the nucleon

resonances near the threshold.

there is considerable discrepancy between the theory and

experiment. Therefore, to cure this

γp ―› K*Λ(K*,K,κ,N,Λ,Σ,Σ*)

Page 13: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Total Cross section

γp ―› K*Λ(K*,K,κ,N,Λ,Σ,Σ*)

Page 14: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Nucleon Resonances ◈ Among the nucleon resonances reported in PDG, we take into account only three- or four-star resonances.

◈ The threshold energy of K*Λ is 2008 MeV. 1) Mass(N*) < 2008 MeV 2) Mass(N*) > 2008 MeV N* = P11(1440, 1/2+)**** N*= G17(2190, 7/2- )**** D13(1520, 3/2 -)**** H19(2220, 9/2+)**** S11(1535, 1/2 - )**** G19(2250, 9/2- )**** S11(1650, 1/2 - )**** I 11(2600,11/2- )*** D15(1675, 5/2 -)**** F15(1680, 5/2+)**** D13(1700, 3/2 -)*** P11(1710, 1/2+)*** P13(1720, 3/2+)****

? ?

Page 15: K*Λ(1116) Photoproduction  and Nucleon resonances

1) Mass(N*) < 2008 MeV

◆ ◆ All values of the helicity amplitudes are given experimentally,

so so the transition magnetic moments are calculated easily.

3. Nucleon Resonances

Page 16: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Nucleon Resonances

◆ The coupling strength of ggK*N*ΛK*N*Λ is unknown.

▶ We treat it as a free parameter, and by varying the value

of ggK*N*ΛK*N*Λ, we can know which nucleon resonance would

dominate the process.

Assumption :

Considering the Nijmegen potential, gK*NΛ= -4.26, kK*NΛ=2.66,

we assume that the ratio of gK*N*Λ and kK*N*Λ can be similar,

~1.6.

Page 17: K*Λ(1116) Photoproduction  and Nucleon resonances

1. P11(1440,1/2+)

2. P11(1710,1/2+)

3. Total Cross section

Spin 1/2+ N* resonances are negligible.

Page 18: K*Λ(1116) Photoproduction  and Nucleon resonances

3. S11(1535,1/2-)

3. Total Cross section

For ||ggK*N*ΛK*N*Λ| = 7.0~9.0| = 7.0~9.0,

it’s in a good agreement with the data.

Page 19: K*Λ(1116) Photoproduction  and Nucleon resonances

4. S11(1650,1/2-)

3. Total Cross section

For ||ggK*N*ΛK*N*Λ| = 5.0~6.0| = 5.0~6.0,

it’s in a good agreement with the data.

Page 20: K*Λ(1116) Photoproduction  and Nucleon resonances

6. D13(1700,3/2-)

5. D13(1520,3/2-)

3. Total Cross section

Spin 3/2- N* resonances are relatively small.

Page 21: K*Λ(1116) Photoproduction  and Nucleon resonances

7. P13(1720,3/2+)

3. Total Cross section

Spin 3/2+ N* resonance is relatively small.

Page 22: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Total Cross section8. F15(1680,5/2+)

9. D15(1675,5/2-)

Spin 5/2 N* resonances are negligible.

Page 23: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Total Cross sectionAmong the nucleon resonances less than 2008 MeV, P11(1440), P11(1710), D15(1675), and F15(1680) are almost negligible.

D13(1520), D13(1700), and P13(1720) contributeslightly.

S11(1535) and S11(1650) are most responsiblefor reproducing the data, when their values of the coupling constants are |g|gK*N*ΛK*N*Λ(1535)| = 7.0~9.0(1535)| = 7.0~9.0 and and |g|gK*N*ΛK*N*Λ(1650)| = 5.0~6.0(1650)| = 5.0~6.0..

|g|gKN*ΛKN*Λ(1535)| = 1.0~2.0 (1535)| = 1.0~2.0 from the chiral unitary from the chiral unitary modelmodel

Page 24: K*Λ(1116) Photoproduction  and Nucleon resonances

3. Nucleon Resonances

◆ Except for N*(2190), the helicity amplitudes are not known experimentally. Moreover, only the ratio of the N*(2190)’s helicity amplitude is given.

2) Mass(N*) > 2008 MeV

◆ The coupling strength of ggK*N*ΛK*N*Λ is obtained by the SU(6) quark model.

▶ As a trial, we will take into account only G17(2190). Related works are under progress.

Page 25: K*Λ(1116) Photoproduction  and Nucleon resonances

4. Conclusion

◈ We investigated the K* photoproduction off the nucleon,

γN ―›K*Λ(1116)γN ―›K*Λ(1116), within the tree level approximation.

◈ In addition to K*, K, κ, N, Λ, Σ, Σ* contributions, we considered moremore

nucleon resonancesnucleon resonances to explain the discrepancy between the to explain the discrepancy between the previousprevious

theoretical result and experimental data in the near theoretical result and experimental data in the near threshold region.threshold region.

◈ Among them, Among them, SS1111(1535) (1535) and and SS1111(1650)(1650) are responsible for are responsible for

rreproducing the data, when their values for the coupling the data, when their values for the coupling constant constant

are are |g|gK*N*ΛK*N*Λ(1535)| = 7.0~9.0 and |g(1535)| = 7.0~9.0 and |gK*N*ΛK*N*Λ(1650)| = 5.0~6.0(1650)| = 5.0~6.0..

Page 26: K*Λ(1116) Photoproduction  and Nucleon resonances

5. Outlook

1.1. We will include We will include more higher-spin resonances more higher-spin resonances usingusing experimentalexperimental

and theoretical information.and theoretical information.

2. 2. Chi-square fittingChi-square fitting will be taken into account. will be taken into account.

3. 3. Differential cross section,Differential cross section,

Double polarization observables. Double polarization observables.

4. Extending present framework into4. Extending present framework into general vector meson- general vector meson-baryonbaryon

photoproduction.photoproduction.

Page 27: K*Λ(1116) Photoproduction  and Nucleon resonances

Thank you very much