1. Vector meson photoproduction
Vector meson photoproduction
Electromagnetic structure of spin-1 vector boson
CLAS
B. G. Yu & K.-J. Kong (Korea Aerospace Univ.)

4. Photoproduction of charged

9. Charged process

10. Reggeization: charged case

12. Observables

20. Reggeization: neutral case

23. Photoproduction of

26. Reggeization

34.
Summary & Perspective

36. Back up

38. EM structure of charged vector meson

39. Motivation Why vector meson photoproduction ?
Motivation
Why vector meson photoproduction ?
Study electromagnetic structure of spin-1 vector boson
Charge + magnetic dipole moment + electric quadrupole moment
Study N* resonances associated with strangeness production
rho(770) thres. energy W ~ 1.7 GeV ; nucleon poles are far below the threshold & N* resonances apparent from PDG.
K*(892) thres. energy W ~ 2 GeV ; no N* resonances from PDG.
Charged process is special ; dominated by t-ch. vector meson exch.
Neutral process is special ; dominated by t-ch. Pomeron exch.
Effective Lagrangian approach with cpl.const. within physical range
Production mechanism of charged process not understood yet
due to a difficulty in gauge prescription for spin-1 vector boson exch.

40. Summary & Perspective Why K* Lambda photoproduction ?
Summary & Perspective
Why K* Lambda photoproduction ?
=A good place to study K* meson properties
Decisive role of the vector meson with magnetic dipole moment + electric quadrupole moment
- sign & magnitude of magnetic dipole
- gauge prescription = on-shell + transversality
Clean background to investigate EM properties of vector meson
- dominating t-ch. meson exchange ; K*(892) + K(494)
- Rho + (Delta + N*) ---- K* + (… )
Extraction of EM form factor of K* from electroproduction
Reggeized meson exchanges at forward angle
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41. K*Lambda cross section @CLAS/JLab (hep-ex/0601010)
K*Lambda cross (hep-ex/ )

42. K*Sigma+ cross section @CLAS/JLab PRC75,042201(2007)

43. K*Sigma+ cross section @CBELSA/TAPS EPJA35,333(2009)
K*Sigma+ cross EPJA35,333(2009)

44. Photoproduction amplitude

45.
Model calculation
Q. Zhao et al., PRC (2001)

46. K*Sigma+ cross section
K*Sigma+ cross section

47. Model calculation
Oh & Kim PRC73, (2006)

48.
Model calculation
S. Ozaki et al., PRC (2010)

49. Effective Lagrangians
Effective Lagrangians

50. Photon-V-V vertex

51.
Pole model
Photoproduction current

52.
Gauge invariance I

53.
Gauge invariance II

54. Coupling constants

55. Rho+

56. Rho+ model II

57. Rho-

58. Rho- model II

60. K* model I

61. K* model II

62. Cutoff-dependence model II

63. K+K*+contact term model II

64. Differential cross sections model II

65. Photoproduction amplitude
Photoproduction amplitude

66.
Gauge invariance

67.
Regge model

68. Photoproduction amplitude

71. Angular Distrib. K*Lambda
Numerical results
Angular Distrib. K*Lambda

72. Angular distrib. & Total cross section

73. Angular distrib. & Photon polarization

74. Summary & perspective gamma p  K* Lambda ~ t-ch. meson exch.
Summary & perspective
gamma p  K* Lambda ~ t-ch. meson exch.
Pole model + Reggeized t-ch. Pole  complementary to each other to investigate production mechanism.
3. Magnetic dipole moment of K* meson  crucial to explain experiment.
4. Y* resonance in the u-ch.  base for studying Y* in the backward region.
5. Extension to electroproduction  advantageous to extract EM form factors of the spin-1 K* vector meson.

75. K*

76. K*

77. Rho+

78. Rho-

79. Exchange Degeneracy Duality of s-ch. resonance to t-ch. Regge pole
Exchange Degeneracy
Duality of s-ch. resonance to t-ch. Regge pole