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Xian-Hui Zhong

Xian-Hui Zhong. Department of Physics, Hunan Normal University. The S=-1 baryons in the K - p scattering. In c ollaborat ion with : Qiang Zhao. Motivation. New data from Crystal Ball.

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Xian-Hui Zhong

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  1. Xian-Hui Zhong Department of Physics, Hunan Normal University The S=-1 baryons in the K-p scattering In collaboration with: Qiang Zhao

  2. Motivation New data from Crystal Ball The recent measurements of K-pneutrals reactions at crystal ball had been reported at eight momentum beams between514 and 750 MeV/c were reported, which provides us a goodopportunity to study the properties of these low-lying ΣandΛ resonances systematically R. Manweiler et al, PRC77, 015205 (2008); S. Prakhov at el, 0812.1888 The unwell-established resonances The S=-1 baryon spectrum is still not well established, such as the quantum numbers of Σ(1480,1560,1670,1690) (bumps) in PDG are still unknown.

  3. Chiral quark model Diagrams of the processes The meson is looked as a pointed-like particle, which couples to the quarks. X.H.Zhong, Q.Zhao, J.He and B.Saghai, PRC76,065205(2007); X.H Zhong, Qiang. Zhao, PRC79,045202(2009)

  4. Chiral quark model Quark-meson couplings For pseudoscalar-mesons: For vector-mesons:

  5. Chiral quark model The possible resonances in the reactions according to the quark model

  6. Chiral quark model The partial wave amplitudes up to n=2 shell X.H.Zhong, Q.Zhao, J.He and B.Saghai, PRC76,065205(2007); X.H Zhong, Qiang. Zhao, PRC79,045202(2009)

  7. Results Resonance parameters There are very low mass S wave states Σ(1480,1560) !

  8. Results couplings large couplings of Σ resonances to Λπ are needed, large coupling of Λ (1520) to KN is needed! Small coupling of Λ(1670) to KN is needed. In agreement with the UChPT results [E.Oset, A.Ramos and C.Bennhold,PLB527,99(2002)].

  9. Results Total cross sections

  10. Results (K-pΛπ0) Differential cross sections

  11. Results (K-pΣ0π0) Differential cross sections

  12. Results (K-pK0n) Differential cross sections

  13. Results (K-pΛπ0) Obvious evidence of Σ(1480) ! Oller et al., also predicted such a low mass state with UChPT (EPJA28,63;31,527). S wave contributions

  14. Results (K-pΛπ0) D wave contributions

  15. Results (K-pΛπ0) P wave and background contributions u and t channel contributions are important !

  16. Results ( K-pΣ0π0) S and D wave contributions

  17. Results ( K-pΣ0π0) P wave and background contributions u and t channel contributions are important !

  18. Results ( K-pK0n) S wave contributions Further evidences of Σ(1480) are found!

  19. Results ( K-pK0n) D wave contributions

  20. Results ( K-pK0n) P wave and background contributions The higher P waves JP=3/2+ are important in the region P_k~1000 MeV/c

  21. Summary • We investigated the K-p reactionswith a chiral quark model. A successful description of the differential cross sections and the cross sections at low energy region was obtained. • Obvious evidences of Σ(1480) with broad width and Σ(1560) are found in the reactions. • The t and u channel contributions are important. • The amplitudes of Σ resonances are larger than the quark model predictions, which implies that the Σ resonances contain q-qbar components. The q-qbar components also exist in Λ(1405). • The large coupling of Λ(1520) to KN implies that the Λ(1520) contains s-sbar components.

  22. Thank you very much!

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