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Il Nuovo Cimento (1955-1965)

, Volume 5, Issue 1, pp 111–122 | Cite as

On the Λ-nucleon force and the binding energy of the light hyperfragments

  • N. Dallaporta
  • F. Ferrari
Article

Summary

The problem of the binding of a Λ-particle in nuclear matter is considered, assuming that the force acting between Λ and nucleon is due not only to the K-field but also to the π-field; the interaction schemes are:\(\Lambda \to N + \bar K, N \to \Lambda + K, N + \pi , \Lambda \leftarrow \to \Sigma + \pi \). The calculations are done assuming the d’Espagnat and Prentki hamiltonian, with both scalar and pseudovector coupling (spin of the Λ and the Σ equal 1/2). A good fit to the experimental values for the binding energy of the Λ in light hyperfragments is obtained, if one assumes that the interaction constants for both the π and K-forces are of the same order of magnitude as the coupling constant of the ordinary nuclear forces: with this assumption the π-force turns out to be the more important for the binding.

Riassunto

Si studia l’energia di legame delle Λ in materia nucleare, supponendo che l’interazione Λ-nucleone sia dovuta non solo al campo K ma anche al campo π; le reazioni considerate sono\(\Lambda \to N + \bar K, N \to \Lambda + K, N + \pi , \Lambda \leftarrow \to \Sigma + \pi \). I calcoli sono stati eseguiti assumendo l’hamiltoniano di d’Espagnat e Prentki, con accoppiamento sia scalare sia pseudovettore (spin della Λ e della Σ uguale a 1/2). L’energia di legame della Λ è in buon accordo con i dati sperimentali se si fa l’ipotesi che le costanti di interazione per le forze π e K siano dello stesso ordine di grandezza della costante di accoppiamento delle ordinarie forze nucleari: in questo caso la forza π risulta prevalente rispetto alla forza K.

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References

  1. (1).
    E. Diana andF. Duimio:Nuovo Cimento,2, 370 (1955);K. Nishijima:Prog. Theor. Phys.,14, 527 (1955);G. Wentzel:Phys. Rev.,101, 835 (1956);R. Gatto:Nuovo Cimento, 3, 499 (1956).CrossRefGoogle Scholar
  2. (2).
    R. H. Dalitz:Phys. Rev.,99, 1551 (1956).MathSciNetGoogle Scholar
  3. (3).
    B. D’Espagnat andJ. Prentki:Nuclear Physics,1, 38 (1956).MathSciNetGoogle Scholar
  4. (4).
    M. Ruderman andR. Karplus:Phys. Rev.,102, 247 (1956).ADSCrossRefGoogle Scholar
  5. (5).
    A. Bonetti, M. Baldo Ceolin, D. Greening, S. Limentani, M. Merlin andG. Vanderhaege:Torino Conference, September 1956 (in course of publication onSuppl. Nuovo Cimento).Google Scholar
  6. (6).
    T. D. Lee andC. N. Yang:Phys. Rev.,102, 290 (1956).ADSCrossRefGoogle Scholar
  7. (7).
    F. J. Dyson:Phys. Rev.,73, 929 (1948);L. L. Foldy:Phys. Rev.,84, 168 (1951);S. S. Schweber, H. Bethe andF. Hoffmann:Meson and Fields, I (New York, 1955), p. 446.ADSCrossRefMATHGoogle Scholar
  8. (8).
    K. A. Brueckner andK. W. Watson:Phys. Rev.,92, 1023 (1953). Indicated in the following as B. W.MathSciNetADSCrossRefMATHGoogle Scholar
  9. (9).
    Z. Klein:Phys. Rev.,94, 195 (1954);E. A. Power:Nuovo Cimento,3, 323 (1954).ADSCrossRefMATHGoogle Scholar
  10. (10).
    W. Fry:Seminar at Columbia University (New York, April 1956).Google Scholar
  11. (11).
    R. Hofstadter et al.:Proc. Sixth Annual Rochester Conference, 1956.Google Scholar
  12. (12).
    R. Hofstadter et al.:Proc. Fifth Annual Rochester Conference 1955.Google Scholar
  13. (13).
    R. H. Dalitz:Proc. Sixth Annual Rochester Conference 1956;Seminar at Padua University, May 1956.Google Scholar

Copyright information

© Società Italiana di Fisica 1957

Authors and Affiliations

  • N. Dallaporta
    • 1
    • 2
  • F. Ferrari
    • 1
    • 2
  1. 1.Istituto di Fisica dell’UniversitàPadova
  2. 2.Istituto Nazionale di Fisica NucleareSezione di PadovaItaly

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