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Il Nuovo Cimento (1955-1965)

, Volume 27, Issue 3, pp 724–747 | Cite as

Interpretation of pion-nucleon scattering results in the resonance region

  • W. M. Layson
Article

Summary

Recognizing that present information on pion-nucleon scattering in the range (300÷1500) MeV is insufficient for a complete and unambigous analysis in terms of angular-momentum amplitudes, a study has been made employing restrictive assumptions related to the higher resonances. The π-p angular distribution data are found consistent with resonances of (T,J)=(1/2,3/2) and (1/2,5/2+) at 600 and 900 MeV. A plausible, but nonunique, set of amplitudes has been determined, and the only significant departure from a simple behaviour is in the amplitude for the (1/2,1/2+) state, which could contain a resonance at 900 MeV. The Λ0K0 production cross-section shows features in agreement with such a resonance. A proposed phenomenological model based on the important role of the (3/2,3/2+) pion-nucleon state predicts the existence of eight resonances below 1500 MeV. Present experimental results are compared with the model and suggestions are made regarding possible tests.

Riassunto

Avendo riconosciuto che le attuali cognizioni sullo scattering pione-nucleone nel campo (300÷1500) MeV sono insufficienti per un’analisi completa e priva di ambiguità in termini delle ampiezze del momento angolare, si è fatto uno studio introducendo ipotesi restrittive relative alle risonanze più elevate. Si è trovato che i dati della distribuzione angolare π-p sono in accordo con risonanze di (T, J)=(1/2,3/2) e (1/2, 5/2+) a 600 e 900 MeV. Si è determinato un gruppo di ampiezze plausibili, ma non unico, e la sola discordanza significativa è nell’ampiezza dello stato (1/2,1/2+), che potrebbe contenere una risonanza a 900 MeV. La sezione d’urto per la produzione Λ0K0 presenta caratteristiche corrispondenti a questa risonanza. Si propone un modello fenomenologico basato sul ruolo importante dello stato pione-nucleone (3/2,3/2+), che predice l’esistenza di otto risonanze al di sotto di 1500 MeV. Si confrontano gli attuali risultati sperimentali col modello e si suggeriscono possibili verifiche.

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References

  1. (2).
    R. F. Peierls:Phys. Rev.,118, 323 (1960).ADSCrossRefGoogle Scholar
  2. (3).
    B. J. Moyer:Rev. Mod. Phys.,33, 367 (1961).ADSCrossRefGoogle Scholar
  3. (4).
    I. Derado andN. Schmitz:Phys. Rev.,118, 309 (1960);J. I. Shonle:Phys. Rev. Lett.,5, 156 (1960), UCRL 9362;A. R. Erwin andJ. K. Kopp:Phys. Rev.,109, 1364 (1958);L. Bagett: UCRL 8302;S. Bergia, L. Bertocchi, V. Borelli, C. Brautti, L. Chersovani, L. Lavatelli, A. Minguzzi-Ranzi, R. Tosi, P. Waloschek andV. Zoboli:Nuovo Cimento,15, 551 (1960);M. Chrétien, J. Leitner, N. P. Samios, M. Schwarz andH. Steinberger:Phys. Rev.,108, 383 (1957);L. Bertanza, R. Carrara, A. Drago, P. Franzini, I. Mannelli, P. V. Silvestrini andP. H. Stokes:Nuovo Cimento,19, 467 (1961);L. K. Goodwin, R. Kenney andV. Perez-Mendez:Phys. Rev. Lett.,3, 522 (1959), UCRL 9119;F. Grard, G. Macleod, L. Montanet, M. Cresti, R. Barloutaud, C. Choquet, J. M. Gaillard, J. Heughebaert, A. Levèque, P. Lehmann, J. Meyer andD. Revel:Nuovo Cimento,22, 193 (1961).ADSCrossRefGoogle Scholar
  4. (5).
    J. W. Cronin:Phys. Rev.,118, 824 (1960).ADSCrossRefGoogle Scholar
  5. (6).
    E. F. Beall, B. Cork, P. G. Murphy, W. A. Wenzel, C. M. P. Johnson andL. J. Koester Jr.: UCRL 9833.Google Scholar
  6. (7).
    W. D. Walker, J. Davis andW. D. Shepard:Phys. Rev.,118, 1616 (1960).ADSGoogle Scholar
  7. (8).
    C. D. Wood, T. J. Devlin, J. A. Helland, M. J. Longo, B. J. Moyer andV. Perez-Mendez:Phys. Rev. Lett.,6, 481 (1961).ADSCrossRefGoogle Scholar
  8. (9).
    W. M. Layson:Thesis, M.I.T. Physics Dept. (1961), unpublished.Google Scholar
  9. (10).
    C. D. Wood: UCRL 9507;D. H. Frisch andM. Wahlig: private communication.Google Scholar
  10. (11).
    L. Bertanza, P. L. Connolly, B. B. Culwick, F. R. Eisler, T. Morris, R. Palmer, A. Prodell, N. P. Samios:Phys. Rev. Lett.,8, 332 (1962);F. Eisler, P. Franzini, J. M. Gaillard, A. Garfinkel, J. Keren, R. Plano, A. Prodell andM. Schwartz:Rev. Mod. Phys.,33, 436 (1961).ADSCrossRefGoogle Scholar
  11. (12).
    S. E. Wolf, N. Schmitz, L. J. Lloyd, W. Laskar, F. S. Crawford, J. Button, J. A. Anderson andG. Alexander:Rev. Mod. Phys.,33, 439 (1961); alsoF. S. Crawford: private communication toB. T. Feld.ADSCrossRefGoogle Scholar
  12. (13).
    B. T. Feld:Proc. of the 1958 International Conference on High-Energy Physics (CERN Geneva, 1958), p. 15.Google Scholar
  13. (14).
    A. Kanazawa:Phys. Rev.,123, 997 (1961).MathSciNetADSCrossRefGoogle Scholar
  14. (15).
    J. Steinberger:Proc. of the 1958 International Conference High-Energy Physics (CERN Geneva, 1958).Google Scholar
  15. (16).
    J. Blatt andV. F. Weisskopf:Theoretical Nuclear Physics (New York, 1952).Google Scholar
  16. (17).
    T. J. Devlin, B. C. Barish, W. N. Hess, V. Perez-Mendez andJ. Solomon:Phys. Rev. Lett.,4, 242 (1960); UCRL 9017;T. J. Devlin: UCRL 9548.ADSCrossRefGoogle Scholar
  17. (18).
    S. Fernbach, R. Serber andT. B. Taylor:Phys. Rev. Lett.,75, 1352 (1949).ADSGoogle Scholar
  18. (19).
    H. A. Bethe andR. R. Wilson:Phys. Rev.,83, 690 (1951).ADSCrossRefGoogle Scholar
  19. (20).
    R. Omnès andG. Valladas:Proc. of the Aix-en-Provence International Conference on Elementary Particles (1961).Google Scholar
  20. (21).
    B. C. Maglić, B. T. Feld andC. A. Diffey:Phys. Rev.,123, 1444 (1961).ADSCrossRefGoogle Scholar
  21. (22).
    P. Carruthers:Phys. Rev. Lett.,4, 303 (1960);W. Wong andM. Ross:Phys. Rev. Lett.,3, 398 (1959).ADSCrossRefGoogle Scholar
  22. (23).
    Y. Tomozawa:Nucl. Phys.,28, 160 (1961).CrossRefGoogle Scholar
  23. (24).
    S. J. Lindenbaum andR. M. Sternheimer:Phys. Rev.,123, 333 (1961).ADSCrossRefMATHGoogle Scholar
  24. (25).
    V. Alles-Borelli, S. Bergia, E. P. Ferreira andP. Waloschek:Nuovo Cimento,14, 211 (1959).CrossRefGoogle Scholar
  25. (27).
    J. H. Foote, O. Chamberlain, E. H. Rogers andH. M. Steiner:Phys. Rev. Lett.,4, 30 (1960).ADSCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1963

Authors and Affiliations

  • W. M. Layson
    • 1
  1. 1.CERNGeneva

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