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Hyperons analogous to L(1405)

Hyperons analogous to L(1405). Yongseok Oh (Kyungpook National University, Korea). 5 th APFB Conference August 22-26, 2011, Seoul, Korea. Overview. Introduction Bound state approach to the Skyrme model Outlook. 1. Introduction. Hyperon spectrum

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Hyperons analogous to L(1405)

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  1. Hyperons analogous to L(1405) Yongseok Oh (Kyungpook National University, Korea) 5th APFB Conference August 22-26, 2011, Seoul, Korea

  2. Overview • Introduction • Bound state approach to the Skyrme model • Outlook

  3. 1.Introduction • Hyperon spectrum • Completeness of the observed hyperon resonances • Theoretical models for hyperon structure • Structure of L(1405) • uds • Five quark • K-bar N bound state - S baryon analogous to L(1405)? PDG

  4. X spectrum P is not directly measured Cf. spin of W- (=3/2) was confirmed only recently by BaBar, PRL 97 (2006)

  5. Experiments on multi-strangeness No meaningful information on X spectrum Open a new window for studying baryon structure PDG 2008

  6. Questions The 3rd lowest state CLAS: PRC 76 (2007) Babar: JP of X(1690) is 1/2- PRD78 (2008)

  7. Summary PRC 75 QM (Pervin, Roberts) 1325 1891 2014 1320 (expt.) 1520 1934 2020 1530 (expt.) 1725 1811 1820 (expt.) 1759 1826 Expt: X(1620)*, X(1690)*** : the 3rd lowest state

  8. Highly model-dependent !

  9. bound kaon 2. Bound state approach to the Skyrme model Bound state approach(Callan, Klebanov) SU(3) is badly broken Treat light flavors and strangeness on the different footing L = LSU(2) + LK/K* Soliton provides background potential which traps K/K* (or heavy) meson

  10. Bound state model 270 MeV energy difference Mass formula • Includes parameters • They should be computed with a given Lagrangian (dynamics). • Or fix them to known masses and then predict.

  11. Some details Kaons: one in p-wave and one in s-wave J=Jsol + Jm (Jm = J1 + J2) Jsol: soliton spin (=1/2), J1(J2): spin of the p(s)-wave kaon (=1/2) Jm = 0 and 1: both of them can lead to JP = 1/2-X states Therefore, two JP = 1/2-X states and one JP = 3/2-X state In this model, it is natural to have two JP = 1/2-X states and their masses are close to each other. Clearly, different from quark models Other approaches Unitarized extension of chiral perturbation theory Ramos, Oset, Benhold PRL 89 (2002) 1/2- state at 1606 MeV Garxia-Recio, Lutz, Nieves, PLB 582 (2004) X(1620) and X(1690) are 1/2- states

  12. Hyperon spectrum parity undetermined negative parity 290 MeV positive parity 285 MeV 289 MeV

  13. Hyperon spectrum Recently confirmed by COSY PRL 96 (2006) Babar: JP of X(1690) is 1/2- PRD 78 (2008) NRQM predicts 1/2+ High precision experiments are required! W’s would be discovered in future. spin-parity YO, PRD 75 (2007)

  14. Outlook

  15. Heavy quark baryons • Similar mass splitting between parity partners • Lc(1/2+): 2286 MeV, Lc(1/2-): 2595 MeV • The mass difference between the two = 309 MeV • Potential is almost flavor-blind but gives richer spectrum forheavy-quark baryons • More analyses are needed

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