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K - - p “atom” identified as L (1405)

“ Resonant formation of the K - p quasi-bound state in stopped-K - absorption in 4 He, 3 He and d : Experimental test of the Λ(1405) vs Λ(1420) Ansatz “ Toshimitsu Yamazaki, Jafar Esmaili and Yoshinori Akaishi at ECT* October 15, 2009. K - - p “atom” identified as L (1405).

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K - - p “atom” identified as L (1405)

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  1. “Resonant formation of the K-p quasi-bound state in stopped-K- absorption in 4He, 3He and d: Experimental test of the Λ(1405) vs Λ(1420) Ansatz“Toshimitsu Yamazaki, JafarEsmaili and Yoshinori Akaishiat ECT* October 15, 2009

  2. K- - p“atom” identified as L(1405) fundamental building block of Kbar nuclear condensed matter • Strongly attractive K- - p -> deep and strong binding • Molecular nature of K-pp • Evolution of K- nuclear systems * Superstrong nuclear force -> Kaon condensation • All depend on the • L(1405) AnsatzValid ?

  3. Alternative scenario: L*(1420) 2-pole Ansatz -> shallow and weak binding regime

  4. Avoid confusing prejudices and wishful thinking: Robust experimental signature: urgently called for L*=K-p as a Feshbach resonance Coupled channels 1: Kbar N 2: S p For a given M: --> s11, s12, s22 Single-pole or double-pole ? More Confusion: T21 or T22 ?

  5. KN->Sp invariant mass spectra 2: Sp 1: KN Arbitrary unit KbarN missing mass spectrum Sp->Sp invariant mass spectra Escape of K Conversion s1/2[MeV] L(1405) L(1420) Characteristics of T22 : rising above KbarN threshold

  6. COSY-ANKEp + p -> K+ + Y0 + p-> S0+ p0 -> L + g + p0HADESFOPI

  7. Hemmingway S+(1660) -> (Sp)0+ p+ • Zychor pp -> K+ (S0p0)p DD91, Hyodo-Weise use T22 Sp -> Sp without justification Serious discrepancy above the KbarN threshold

  8. Interpretation of Zychor’s data SPECTRAL SHAPE Realistic treatment * Sp emission threshold * K- + p threshold CAUTION !! For a broad resonance the apparent peak position deviates downward M~1406 G~40 most likely, but Need more statistics !

  9. Is this a L(1405) peak? No! It is a quasi-free peak Discovery of L(1405): Alston et al. (1961)K- + p -> (Sp)0 + p+ + p- New problem raised: Is it true?! No, not true Stopped K- in 4He (Sp)0 (Sp)+-

  10. arXiv: _0906.0505 • Resonant formation (nuclear tuning) K- + “p”L* S + pgoverned byT21 K- + “p” S + p(quasi-free) constrained by spectator momentum arXiv:0909.2573

  11. M [MeV/c2] Free Inv.-mass Th. Proj. Inv.-mass Th.  partial invariant-mass spectra

  12. S orbit abs. G. Pot. =35 MeV 2 M* (MeV/c2) 2 ,s :  invariant-mass spectra

  13. d target: small and large momentum components Resonant formation of L(1405) distinctly visible

  14. Hyodo-Weise (chiral) Akaishi-Yamazaki (phenom) MSp[MeV/c2] Sp invariant-mass spectrum from stopped K- onD

  15. No effect of the 2nd pole:T21 dominanceonly the 1st pole is relevant

  16. Two-pole form of L(1405) J. Revai & N.V. Shevchenko, Phys. Rev. C 79 (2009) 035202 Sp invariant-mass spectrum from stopped K- onD C3G pot. 2nd pole effect is negligible ! one pole A-Y 1410-64 R-S One-pole R-S Two-pole MSp[MeV/c2] 2nd pole 1st pole No visible effect of the 2nd pole

  17. How can we determine ?Simulation stopped K- on dExperimental design-> J-PARC ProposalT. Suzuki et al.

  18. Chi2 analysis of simulation data

  19. In-flight K-d -> (Sp) n

  20. K lab= 5 MeV/c 1420 1405 Resonant QF 80 MeV/c 120 MeV/c 160 MeV/c Stopped kaon does not provide a good set up to learn about L(1405). 200 MeV/c covers! Non-resonant QF All are normalized to 1 M(Sp) [MeV/c2] Low-momentum K-+D reaction QF Spectator process dominates! K lab= 200 MeV/c D. Jido, E. Oset & T. Sekihara, Eur. Phys. J. K lab= 120 MeV/c X K lab= 5 MeV/c Projection spectra of 3-body Dalitz

  21. No effect of the 2nd pole:T21 dominanceonly the 1st pole is relevant

  22. decreases! cf. P. Kienle, Y. Akaishi & T. Yamazaki, Phys. Lett. B 632 (2006) 187 Dalitz plot for spectator process O. Braun et al., Nucl. Phys. B 124 (1977) 45 QF Cusp M(Lp) [MeV/c2] S(1385) L(1405) M(Lp) [MeV/c2] M(Sp) [MeV/c2]

  23. JOS ascribed the component around M~1400 to S*(1385) to conclude L*(1420) • More statistics necessary: • A proposed experiment at J-PARC

  24. No conclusive results on L(1405) yet, but many promising experiments NEAR FUTURE EXPERIMENTS Highly Awaited K- + d K-p + nMM (n) KEK, both at rest and in-flightK- + 3He  K-p + dMM (d) AMADEUS, at rest, J-PARC p + p K+ + (Sp) + p HADES

  25. Thank you very much

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