Advertisement

Il Nuovo Cimento (1955-1965)

, Volume 35, Issue 3, pp 713–730 | Cite as

Single pion production in π-p interactions at 2.75 GeV/c

  • Saclay-Orsay-Bari-Bologna Collaboration
  • J. P. Baton
  • A. Berthelot
  • B. Deler
  • O. Goussu
  • M. Neveu-René
  • A. Rogozinski
  • F. Shively
  • V. Alles-Borelli
  • E. Benedetti
  • R. Gessaroli
  • P. Waloschek
Article

Summary

A liquid hydrogen bubble chamber investigation of πp interactions has been carried out at a momentum of 2.75 GeV/c. 10645 two-prong events have been measured and the partial cross-sections are: σel=(7.2±0.1) mb, σπ0=(2.8±0.1) mb, σππ+n=(3.9±0.1) mb. In any state of charge, isobar production is very small. ππ mass spectra show a dominant ρ resonance centered at 750 MeV with a full width at half maximum of ⋍130 MeV (σϱ=0.75 mb, σϱ0=1.1 mb; forΔ2⩽8µ2, (σϱϱ0=1/2). There is a slight indication of the presence of the f0f0⩽0.1 mb). Usual tests of the one-pion-exchange mechanism are attempted for the ρ resonances. The ππ elastic cross-section and angular distribution are investigated as a function of the π incident energy. Finally, the narrow peak in the (ππ+) mass spectrum in the region of 780 MeV is discussed.

Riassunto

Con la camera a bolle ad idrogeno liquido si è eseguito uno studio delle interazioni πp ad un impulso di 2.75 GeV/c. Si sono misurati 10645 eventi a due rami e le sezioni d’urto parziali sonoσel=(7.2±0.1) mb, σpππ0=(2.8±0.1) mb, σππ+n=(3.9±0.1) mb. In ogni stato di carica la produzione di isobari è piccolissima. Gli spettri di massa ππ presentano una risonanza ρ predominante centrata a 750 MeV con un’ampiezza totale a metà massimo di ⋍130 MeV (σϱ=0.75 mb, σϱ0=1.1 mb, perΔ2⩽8µ2, σϱϱ0=1/2). Si ha un lieve indizio della presenza dell’f0f0≲0.1 mb). Si tentano le prove usuali del meccanismo di scambio di un pione per le risonanze ρ. Si studiano in funzione dell’energia del π incidente le sezioni d’urto elastico ππ e le distribuzioni angolari. Infine si discute lo stretto picco nello spettro di massa (ππ+), nella regione di 780 MeV.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    Saclay-Orsay-Bari-Bologna Collaboration:Nuovo Cimento,25, 365 (1962).CrossRefGoogle Scholar
  2. (2).
    Saclay-Orsay-Bari-Bologna Collaboration:Nuovo Cimento,29, 515 (1963).CrossRefGoogle Scholar
  3. (3).
    Saclay-Orsay-Bari-Bologna Collaboration: private communication (to be published).Google Scholar
  4. (4).
    L. Stodolsky andJ. J. Sakurai:Phys. Rev. Lett.,11, 90 (1963).ADSCrossRefGoogle Scholar
  5. (5).
    P. Eberhard andM. Pripstein:A possible explanation of the observed asymmetry in ρ0 decay, preprint (1964).Google Scholar
  6. (6).
    W. Fickinger: private communication.Google Scholar
  7. (7).
    V. Hagopian:Thesis, University of Pennsylvania (1963).Google Scholar
  8. (8).
    Z. G. T. Guiragossian: University of California, U.C.R.L. 10731 (1963).Google Scholar
  9. (9).
    E. Pickup, D. K. Robinson andE. O. Salant:Phys. Rev. Lett.,7, 192 (1961).ADSCrossRefGoogle Scholar
  10. (10).
    Saclay-Orsay-Bari-Bologna Collaboration: unpublished results.Google Scholar
  11. (11).
    V. Hagopian andW. Selove:Phys. Rev. Lett.,10, 533 (1963).ADSCrossRefGoogle Scholar
  12. (12).
    L. Bondar, K. Bongartz, M. Deutschmann, H. Weber, D. C. Colley, W. P. Dodd, J. Simmons, B. Tallini, J. Moebes, B. Nellen, G. Winter, E. Lohrmann, E. Raubold, G. Wolf, J. M. Brownlee, I. Butterworth, F. I. Campayne, M. Ibbotson, Y. S. Liu, N. N. Biswas, I. Derado, D. Lüers, G. Lütjens andN. Schmitz:Phys. Lett.,5, 153 (1963).ADSCrossRefGoogle Scholar
  13. (13).
    M. Abolins, R. L. Lander, W. A. W. Mehlhop, Nguyen Huu Xuong andP. M. Yager:Phys. Rev. Lett.,11, 381 (1963).ADSCrossRefGoogle Scholar
  14. (14).
    E. Pickup, D. K. Robinson andE. O. Salant:Phys. Rev. Lett.,9, 170 (1963).ADSCrossRefGoogle Scholar
  15. (15).
    I. J. Veillet, J. Hennessy, H. Bingham, M. Bloch, D. Drijard andP. Negri:Phys. Rev. Lett.,10, 29 (1963).ADSCrossRefGoogle Scholar
  16. (16).
    F. Selleri:Phys. Lett.,3, 76 (1962).ADSCrossRefGoogle Scholar
  17. (17).
    W. D. Walker, J. Boyd, A. R. Erwin, P. H. Satterblom, M. A. Thompson andE. West:Phys. Lett.,8, 208 (1964).ADSCrossRefGoogle Scholar
  18. (18).
    W. J. Fickinger, D. K. Robinson andE. O. Salant:Phys. Rev. Lett.,10, 457 (1963).ADSCrossRefGoogle Scholar
  19. (19).
    S. Glashow:Phys. Rev. Lett.,7, 469 (1961).ADSCrossRefGoogle Scholar
  20. (20).
    G. Feinberg andJ. Bernstein:Nuovo Cimento,25, 1343 (1962).CrossRefGoogle Scholar
  21. (21).
    R. Armenteros, D. N. Edwards, T. Jacobsen, A. Shapira, J. Vandermeulen, Ch. D’Andlau, A. Astier, P. Baillon, H. Briand, J. Cohen-Ganouna, C. Defoix, J. Siaud, G. Ghesquière andP. Rivet:The Sienna International Conference on Elementary Particles (1963), vol.1, p. 296.Google Scholar
  22. (22).
    A. Stanghellini: private communication.Google Scholar
  23. (23).
    M. M. Islam andR. Piñon:Phys. Rev. Lett.,12, 310 (1964).ADSCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1965

Authors and Affiliations

  • Saclay-Orsay-Bari-Bologna Collaboration
  • J. P. Baton
    • 1
  • A. Berthelot
    • 1
  • B. Deler
    • 1
  • O. Goussu
    • 1
  • M. Neveu-René
    • 1
  • A. Rogozinski
    • 1
  • F. Shively
    • 1
  • V. Alles-Borelli
    • 2
    • 3
  • E. Benedetti
    • 2
    • 3
  • R. Gessaroli
    • 2
    • 3
  • P. Waloschek
    • 2
    • 3
  1. 1.Laboratoire de Physique Corpusculaire à Haute Energie, CENSaclay
  2. 2.Istituto di Fisica dell’UniversitàBologna
  3. 3.Istituto Nazionale di Fisica NucleareSezione di BolognaItaly

Personalised recommendations