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Exotic states in S=1 N  K system and low lying ½+ S=-1 resonances

Fri, Sept.4 2009. Exotic states in S=1 N  K system and low lying ½+ S=-1 resonances. Kanchan Khemchandani , Departamento de Fisica , Universidad de Coimbra, Portugal. 19th International IUPAP Conference on Few-Body Problems in Physics 31.08 - 05.09.2009 - University of Bonn / Germany.

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Exotic states in S=1 N  K system and low lying ½+ S=-1 resonances

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  1. Fri, Sept.4 2009 Exotic states in S=1 NK system and low lying ½+ S=-1 resonances • KanchanKhemchandani, • Departamento de Fisica, Universidad de Coimbra, Portugal. 19th International IUPAP Conference on Few-Body Problems in Physics 31.08 - 05.09.2009 - University of Bonn / Germany

  2. Collaborators:Alberto Martinez Torres and Eulogio OsetIFIC-Univ. de Valencia, Spain

  3. Why study the KN system? • A peak K+n invariant mass in the γ n → K+K−n reaction at the Spring8/Osaka  pentaquark • The picture is not clear yet. • KN interaction chiral dynamics repulsive • suggestions  KN bound state • Some investigations have already been done  results not promising • Our study of the KN (S=-1) system  several resonances  revisit KN and make a conclusive study (T. Nakano [LEPS Collaboration], Talk at the PANIC 2002 (Oct. 3, 2002, Osaka); T. Nakano et al., Phys. Rev. Lett. 91, 012002 (2003)) (P. Bicudo, G. M. Marques, Phys. Rev. D69, 011503, 2004; F. J. Llanes-Estrada, E. Oset and V. Mateu, Phys. Rev. C 69, 055203 (2004).)

  4. The KN system. • We started studying the system: • All the interactions are in S-wave . • There are some S=-1, 1/2+ baryonic states in the energy region 1500-1800 MeV whose properties, as spin-parity, are not well understood. 1 2 3 1D. Jido, J. A. Oller, E. Oset, A. Ramos, U. G. Meissner, Nucl. Phys. A 725 (2003) 181-200. 2 T. Inoue, E. Oset, M. J. Vicente Vacas, Phys. Rev. C 65 035204 . 3 J. A. Oller, E. Oset, J. R. Peláez, Phys. Rev. D 59 074001 (199).

  5. 137+1405 =1542 MeV Seems to show up in  production

  6. Some of them seem to remain unexplained in terms of two-body dynamics e.g., a detailed study of the K-p  ppL reaction by Roca et al.4 explains the bulk of the data5, but fails to explain a bump in the L(1600) region. L(1600) 4 L. Roca, S. Sarkar, V. K. Magas and E. Oset, Phys. Rev. C 73, 045208 (2006). 5 S. Prakhov et al., Phys. Rev. C 69, 042202 (2004).

  7. The Formalism • We solve the Faddeev equations • The matrices contain all the possible diagrams where the last two successive interactions are ti and tj • And they satisfy the equations:

  8. In th e Coupled channel approach ( pseudo-scalar mesons of the SU(3) octet + baryons of the 1/2+ octet) → couple to S=-1 ↓ add 

  9. The Formalism • We solve the Faddeev equations • The matrices contain all the possible diagrams where the last two successive interactions are ti and tj • And they satisfy the equations:

  10. ´

  11. Chiral amplitudes

  12. = 0

  13. where

  14. We extend the procedure for the rest of diagrams involving more than three t-matrices • Variables of the eqn: s, s23

  15. Results (S= -1 system , I=1) Σ(1660) P11 [ I(JP)=1(1/2+) ] ***

  16. Σ(1620) S11 [ I(JP)=??] ** Σ(1660) P11 [ I(JP)=1(1/2+) ] *** R. Armenteros et al. Nucl. Phys. B 8, 183 (1968). B. R. Martin et al, Nucl. Phys. B 127, 349 (1977).

  17. Results (S= -1 sytem ,I =0) Λ(1810) P01 [ I(JP)=0(1/2+) ] *** 1750 to 1850 (~ 1810) OUR ESTIMATE

  18. Λ(1600) P01 [ I(JP)=0(1/2+) ] *** 1560 to 1700 (~ 1600) OUR ESTIMATE There are quite possibly two P01 states in this region. 1568 - i 60/2 MeV

  19. The KN system. • We study KNsystem using the same formalism. • We take p 0K0, n 0K+, p −K+, n +K0 as coupled channels. • For which, we take K+0, K0+, K+,  0p,  +n, ηp  charge +1. K+  −, K0  0, K0 ,  −p,  0n, ηn  charge 0. N interaction  +K0,  0K+ for K  charge +1. −K+, 0K0 for  K  charge 0. K interaction K0p, K+n  charge +1 K0n  charge 0 and K+p  charge +2. KN interaction

  20. We find no peak around 1540 MeV. • We find a bump at ~ 1720 MeV with 200 MeV of FWHM in isospin 0 amplitude  with K in isospin 0 configuration and with K mass ~ 800 MeV • No peak in other isospin cases. A bump also in the time delay analysis of KN data N. G. Kelkar et. al. JPG 29, 1001 (2003) K.P. Khemchandani, A. Martinez Torres, E. Oset Phys. Lett. B (2009)

  21. Summary Jp = ?? Ref: AMartínez Torres, K. P. Khemchandani, E. Oset , Phys. Rev. C77:042203,2008; Eur. Phys. J. A35: 295-297,2008

  22. S= -1 sector → four Σ’s and two Λ’s resonances (all the 1/2+ Σ and Λ states in the energy region 1500-1870. ) • S=+1 → a bump around 1720 MeV with ~ 200 MeV of width, No resonance around 1540 MeV.

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