Advertisement

Il Nuovo Cimento (1955-1965)

, Volume 25, Issue 5, pp 973–994 | Cite as

π− Open image in new window scattering in the mandelstam representation

I. — Analyticity of the amplitude and the effect of baryon pole on K+p→Y+π reaction
Article

Summary

Analytic properties of the partial wave amplitude for the K+p→Σ+π reaction are investigated in the total energy space by making use of the Mandelstam representation. The unitarity condition requires the study of the pion-hyperon as well as the kaon-nucleon scattering. The latter interaction will not be important for the long-range part of the interaction, so we neglected the effect of it in this paper. The long-range part of the interaction due to the single-baryon exchange can explain the observed low-energy pion-hyperon resonances. The low-frequency of the Σ-hyperon in theI=1,p3/2 resonance is interpreted by an accidental cancellation of the long-range potential, and hence the universality of the strong pion-baryon interaction still holds for the ΣΣπ interaction. TheI=0 andI=2,p3/2 resonances can be interpreted by the attractive long-range interaction in the pion-hyperon scattering.

Riassunto

Facendo uso della rappresentazione di Mandelstam si studiano le proprietà analitiche dell’ampiezza d’onda parziale per la reazione K+p→Σ+π nello spazio dell’energia totale. La condizione di unitarietà richiede lo studio dello scattering pione-iperone ed anche dello scattering kaone-nucleone. Quest’ultima interazione non è importante nella parte di lungo range dell’interazione, cosicchè in questo lavoro se ne sono trascurati gli effetti. La parte di lungo range dell’interazione, dovuta allo scambio di un solo barione, può spiegare le risonanze pione-iperone di bassa energia osservate. La bassa frequenza dell’iperone Σ nella risonanzaI=1,p3/2 si interpreta come una eliminazione accidentale del potenziale di lungo range, e quindi la universalità delle interazioni forti pione-barione è ancora valida nell’interazione ΣΣπ. Le risonanzeI=0 e 2,p1/2 si possono interpretare come interazioni attrattive di lungo range nello scattering pione-iperone.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    S. G. Frautschi andJ. D. Walecka:Phys. Rev.,120, 1486 (1960).MathSciNetADSCrossRefMATHGoogle Scholar
  2. (2).
    G. F. Chew:S-Matrix Theory of Strong Interactions (New York, 1961).Google Scholar
  3. (3).
    J. Hamilton, T. D. Spearman andW. S. Woolcock:S-Wave Pion-Nucleon Scattering and Pion-Pion Interactions, to be published.Google Scholar
  4. (4).
    M. M. Block, F. Anderson, A. Pevsner, E. Harth, J. Leitner andH. Cohn:Phys. Rev. Lett.,3, 291 (1959).ADSCrossRefGoogle Scholar
  5. (5).
    R. D. Tripp, M. B. Watson andM. Ferro-Luzzi:Phys. Rev. Lett.,8, 175 (1962).ADSCrossRefGoogle Scholar
  6. (6).
    S. Iwao:Nuovo Cimento,23, 516 (1962).CrossRefGoogle Scholar
  7. (7).
    L. W. Alvarez: UCRL-9354 and 1959 Kiev Conference Report on High-Energy Physics. See, also, ref. (5).Google Scholar
  8. (8).
    M. H. Alston: private communication.Google Scholar
  9. (9).
    The analyticity of this reaction in the kaon energy space in the Mandelstam representation was investigated byS. W. MacDowell:Phys. Rev.,116, 774 (1959).MathSciNetADSCrossRefMATHGoogle Scholar
  10. (10).
    F. Ferrari, G. Frye andM. Pusterla:Phys. Rev.,123, 308 (1961).ADSCrossRefGoogle Scholar
  11. (11).
    M. Ferro-Luzzi, R. D. Tripp andM. B. Watson:Phys. Rev. Lett.,8, 28 (1962).ADSCrossRefGoogle Scholar
  12. (12).
    M. H. Alston andM. Ferro-Luzzi:Rev. Mod. Phys.,33, 416 (1961).ADSCrossRefGoogle Scholar
  13. (13).
    M. H. Alston, L. W. Alvarez, P. Everhard, M. L. Good, W. Graziano, H. K. Ticho andS. G. Wojcicki:Phys. Rev. Lett.,6, 698 (1961).ADSCrossRefGoogle Scholar
  14. (14).
    W. R. Frazer andJ. R. Fulco:Phys. Rev.,117, 1603 (1960).MathSciNetADSCrossRefMATHGoogle Scholar
  15. (16).
    Thep 3/2 assignment for this resonance is cited inChew andFrautschi’s paper:Phys. Rev. Lett.,8, 41 (1962).ADSCrossRefGoogle Scholar
  16. (17).
    D. Amati, B. Vitale andA. Stanghellini:Phys. Rev. Lett.,5, 524 (1960).ADSCrossRefGoogle Scholar
  17. (18).
    J. Franklin: to be published.Google Scholar
  18. (19).
    T. D. Lee andC. N. Yang:Phys. Rev.,122, 1954 (1961).ADSCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1962

Authors and Affiliations

  • S. Iwao
    • 1
  1. 1.Department of PhysicsSyracuse UniversitySyracuse

Personalised recommendations