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Photoproductions of hyperons and resonances

Photoproductions of hyperons and resonances. A. Hosaka, RCNP, Osaka University. Role of symmetries in reaction. 1. Chiral symmetry: Kroll-Ruderman term γN –> KΛ(1520) 2. Charge and U-spin γN –> N* 3. SU(3) symmetry violation? γN –> KΛg.s. and the use of polarization. Application to

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Photoproductions of hyperons and resonances

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  1. Photoproductions of hyperons and resonances A. Hosaka, RCNP, Osaka University Role of symmetries in reaction 1. Chiral symmetry: Kroll-Ruderman term γN –> KΛ(1520) 2. Charge and U-spin γN –> N* 3. SU(3) symmetry violation? γN –> KΛg.s. and the use of polarization WS_Heavy_Q

  2. Application to strangeness productions Respecting symmetry Flavor, chiral, • • •   N Y, Q, … Effective Lagrangian approach Various parameters WS_Heavy_Q

  3. 1. Chiral symmetry: Kroll-Ruderman term γN –> KΛ(1520) Nam-Hosaka-Kim Phys.Lett.B579:43-51,2004 Phys.Rev.D71:114012,2005 Phys.Lett.B633:483-487,2006 WS_Heavy_Q

  4. p –> K–(1520): allowed n –> K0(1520): forbidded WS_Heavy_Q

  5. WS_Heavy_Q

  6. Comparison with new LEPS data will be made soon WS_Heavy_Q

  7. 2. Charge and U-spin γN –> N* –> N Ki-Seok Choi, Seung-il Nam , Atsushi Hosaka, Hyun-Chul Kim. Phys.Lett.B636:253-258,2006. WS_Heavy_Q

  8. Photon WS_Heavy_Q

  9. U-spin of antidecuplet WS_Heavy_Q

  10. Selection rule WS_Heavy_Q

  11. New resonance N*(1675)? N –> N* –> N WS_Heavy_Q

  12. WS_Heavy_Q

  13. Model calculation WS_Heavy_Q

  14. WS_Heavy_Q

  15. 3. SU(3) symmetry violation? γN –> KΛg.s. and the use of polarization Ozaki-Nagahiro-Hosaka WS_Heavy_Q

  16. K Basic process of strangeness production K  K • • • N  Important for: Hyper nuclei, hadronic matter, exotics, • • • BUT: The nature of interactions are not well understood WS_Heavy_Q

  17. –3.80 –4.09 1.20 0.78 –0.51 –0.07 Strong Weak 0.67 0.16 –0.31 –0.11 –0.61 –0.37 Strong or weak K* Bennhold et al. NPA695 (2001) 237 SU(3) Is SU(3) broken? Also discussed by Guidal et al. NPA627 (1997) 645 WS_Heavy_Q

  18. Evidence of strong K* ~ Magnetic Use of polarized gamma WS_Heavy_Q

  19. + Magnetic – Electric = Asymmetry WS_Heavy_Q

  20. + Magnetic – Electric = Asymmetry p –> K– LEPS data Sumihama et al. PRC73,035214 (2006) Strongly magnetic => Large K* ? SU(3) Is SU(3) broken? WS_Heavy_Q

  21. WZW induced process A higher order contribution to be added to Born diagrams K g WZW term p K WS_Heavy_Q

  22. WZW induced process A higher order contribution to be added to Born diagrams K g WZW term • Strength is determined by QCD • Contains => Magnetic • Triangle can not be K* • Energy dependent, raising p K p L Actual computation (Ozaki, M2 student) Covariant loop integral Cutoff ~ 1 GeV WS_Heavy_Q

  23.  K g p K N Y, Q, … p L We consider ＋ Using SU(3) parameters WS_Heavy_Q

  24. Where to study p –> K+ 2 SAPHIA 1.5 Resonance region Total cross section [b] 1 W ~ 2.1 GeV 0.5 0 2.4 1.8 2.0 2.2 1.6 W [GeV] WS_Heavy_Q

  25.  p –> K+ W = 2.164 GeV w/o WZW WS_Heavy_Q

  26. Asymmetry 0.5 0 LEPS data, Sumihama et al – 0.5 1 0.9 0.8 0.6 0.7 WS_Heavy_Q

  27. Summary • We have performed s-productions in an effectivelagrangian approach • Some symmetry related predictions are made To be tested further experiments, J-Lab, LEPS, etc • Applicability to variety phenomena including exotics WS_Heavy_Q

  28. WS_Heavy_Q

  29. Summary • We have investigated SU(3) flavor symmetry • Strong magnetic force may be explained by meson clouds induced by the WZW anomaly • Flavor symmetry should be respected • Higher order processes may be relevant for some processes ~ near threshold of new channels WS_Heavy_Q

  30. Asymmetry LEPS 0.5 Weak K* ~ SU(3) A Strong K* 0 Asymmetry A - 0.5 p –> K+ E = 1.9 GeV, W ~ 2.1 GeV WS_Heavy_Q

  31. Role of K* Strong K* => pn asymmetry is not so large Weak => could be large due to contact term Information of n-target is very important WS_Heavy_Q

  32. Something is missing? Spin 3/2 Meson clouds Magnetic Anomalous process WS_Heavy_Q

  33. Summary There are many important but not yet well understood physics • Test of chiral symmetry: KR- and TW terms • SU(3) relations holds? Vector meson couplings WS_Heavy_Q

  34. LEPS data -dependence Asymmetry + : K* dominant – : K dominant WS_Heavy_Q

  35.  dependence LEPS CLAS SAPHIA 1.6 2.4 2 Weak K* ~ SU(3) Strong K* p –> K+ Total SAPHIA E = 1.9 GeV, W ~ 2.1 GeV LEPS WS_Heavy_Q

  36. Strangeness/KK productions Many reasons that we believe it important • Hyper nuclei New era of nuclear physics • Strange nuclear/quark matter Hadronic matter, astrophysics-nuclear physics • Exotic hadrons +, Ds, heavy quark systems • Strange contents of hadrons Strong vacuum structure • . . . WS_Heavy_Q

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