The influence of isobar production on charge ratio and transverse momentum of secondary particles in high energy collisions

  • T. N. Rengarajan


An isobar model in which collision between two particles leads to the creation of only two bodies which by subsequent decay give rise to the observed secondaries has been considered. On the basis of such a model, the charge ratios of pions, kaons andΣ-hyperons inp−p andπ−p collisions have been computed and compared with the available experimental data. Some features of transverse momentum of pions and protons in 24 GeV/cp−p collisions have also been studied. The main conclusions can be summarised as follows:
  1. (1)

    The observed positive excess among pions produced in high energyp−p collisions leading toπ +/π andπ +/π 0 ratios of ∼3 and 1·6 respectively for high momentum pions can be explained on the basis of the isobar model. Further, the fast increase of K+/K ratio as the kaon momentum increases, the high ratio (∼4) ofΣ +/Σ in 24 GeV/cp−p collisions and the existence of a strong positive (negative) excess amongΣ-hyperons produced inπ +p(π p) collisions at various primary energies result, in a natural way, from such a model. The agreement results mainly from the restriction of only two bodies in the final states and does not critically depend on the isospins of produced isobars.

  2. (2)
    The distribution of transverse momentum of pions produced in 24 GeV/cp−p collisions can be represented by the form
    $$N(p_t )dp_s = \frac{{p_1 }}{{po^2 }}\exp .\left( { - \frac{{p_t }}{{po}}} \right)dp_t $$
    withp 0=170 MeV/c. The mean value is 340 MeV/c and is independent of multiplicity of collision.
  3. (3)

    The meanp t of pions is a function of laboratory emission angle. It is low (230 MeV/c) for angles <5°, is more or less a constant (350 MeV/c), between 10° and 30,° and decreases for larger angles.

  4. (4)

    The mean transverse momentum of protons is around 370 MeV/c. There is a trend for the meanp t to increase with prong number for a certain class of events.

  5. (5)

    Unlike the meanp t of pions, the meanp t of protons is independent of primary energy (4–24 GeV) both inp−N andπ−N collisions.

  6. (6)

    The observed features of transverse momentum of pions and protons are consistent with the secondaries being dominantly the decay products of isobars. Further, they indicate a preference for the isobars to decay in cascade rather than through pion resonances.



Transverse Momentum Primary Energy Charge Ratio Strange Particle Cascade Decay 
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7. References

  1. 1.
    Pal, Y. and Peters, B. ..Mat. Fys. Medd. Dan. Vid. Selsk., 1964,33 (15).Google Scholar
  2. 2.
    Damgaard, G. and Hansen, K. H.Proceedings of the Sienna International Conference on Elementary Particles, 1963,1, pp. 643.Google Scholar
  3. 3.
    Dekkers, D., Geibel, J. A., Mermod, R., Webber, G., Willitts, T. R., Winter, K., Jordan, B., Vivargent, M., King, N. M. and Wilson, E. J. N.Phys. Rev., 1965,137 B, 962.CrossRefGoogle Scholar
  4. 4.
    Cocconi, G., Lillethun, E., Scanlon, J. P., Staalbrandt, C. A., Ting, C. C., Walters, J. and Wetherell, A. M.Phys. Lett., 1964,8, 134.CrossRefGoogle Scholar
  5. 4a.
    Bellettini, G., Cocconi, G., Diddens, A. N., Lillethun, E., Scanlon, J. P., Shapiro, A. M. and Wetherell, A. M. Ibid., 1965,18, 167.CrossRefGoogle Scholar
  6. 5.
    Anderson, E. W., Bleser, E. J., Collins, G. B., Fujii, J., Menes, J., Turkot, F., Carrigan, R. A., Jr., Edelstein, R. M., Hien, N. C., McMohon, T. J. and Nedelhaft, I.Phys. Rev. Lett., 1966,16, 855.CrossRefGoogle Scholar
  7. 6.
    Almeida, S. P., Atherton, H. W., Byer, T. A., Dorman, P. J., Forson, A. G., Scharenguivel, J. H., Sendall, D. M. and Westwood, B. A.Phys. Lett., 1965,14, 240.CrossRefGoogle Scholar
  8. 7.
    Damgaard, G., Hansen, K. H., Hooper, J. E., Rengarajan, T. N. and Voss, P.Report from Niels Bohr Institute, Copenhagen, 1966.Google Scholar
  9. 8.
    Diddens, A. N., Galbraith, W., Lillethan, E., Manning, G., Parham, A. G., Taylor, A. E., Walker, T. G. and Wetherell, A. M.Nuovo Cimento, 1964,31, 961.CrossRefGoogle Scholar
  10. 9.
    Fidecaro, M., Finocchiaro, G., Gatti, G., Giacomelli, G., Middelkoop, W. C. and Yamagata, T. Ibid., 1962,24, 73.CrossRefGoogle Scholar
  11. 10.
    Bartke, J., Cooper, W. A., Cozapp, B., Filthuth, H., Goldschmidt-Clermount, Y., L-Montanet, Morrison, D. R. O., Nilsson, S., Peyrou, Ch., Sosnowski, R., Bigi, A., Carrera, R., Rahm, D., Rivet, P. and Solmitz, F. Ibid., 1963,29, 8.CrossRefGoogle Scholar
  12. 11.
    Foelsche, H. W. J., Lopez-Cepero, A., Chien, C. Y. and Krabyill, H. L.Proceedings of the 1964International Conference on High Energy Physics, Dubna, 1964.Google Scholar
  13. 12.
    Smith, G. A. ..Proceedings of the Athens Topical Conference on Recently Discovered Resonant Particles, 1963, pp. 67.Google Scholar
  14. 13.
    Goussu, O., Smadya, G. and Kayas, G. Preprint, 1966.Google Scholar
  15. 14.
    Yamamoto, S. S., Bertanza, L., Monetti, G. C., Rahm, D. C. and Skillicorn, I. O.Phys. Rev., 1964,134 B, 385.Google Scholar
  16. 15.
    Wangler, T. P., Erwin, A. R. and Walker, W. D. Ibid., 1965,137 B, 414.CrossRefGoogle Scholar
  17. 16.
    Bartsch, J., Bondar, L., Speth, R., Hotop, G., Knies, G., Storim, F., Brownloe, J. M., Biswas, N. N., Luers, D., Schmitz, N., Seeliger, R. and Wolf, G. P. Preprint, 1966.Google Scholar
  18. 17.
    Bertanza, L., Culwick, B. B. Lai, K. W., Mittra, I. S., Samias, N. P., Thorndike, A. M., Yamamoto, S. S. and Lea, R. M.Phys. Rev., 1963,130, 786.CrossRefGoogle Scholar
  19. 18.
    Brandt, S., Cocconi, V. T., Czyzewski, O., Danysz, J., Dalpiaz, P. F., Kellner, G., Morrison, D. R. O., Bardadin, M., Hofmkol, T., Pietrowska, Ph., Worblewski, A., Otwinowski, S. and Sosnowski, R.C.E.R.N. Preprint, 1964.Google Scholar
  20. 19.
    Bigi, A., Brandt, S., Cooper, W. A., Aurelia de Marco, Ch. Peyrou, Sosnowski, R. and Worbleswski, A.Nuovo Cimento, 1964,33, 1265.CrossRefGoogle Scholar
  21. 20.
    Bartke, J., Budde, R., Cooper, W. A. Filthuth, H. Goldschmidt-Clermont, Y., MacLeod, G. R., de Marco, A., Minguzzi-Ranzi, A., Montanet, L., Morrison, D. R. O., Nilsson, S., Peyrou, C., Sosnowski, R., Franzinetti, C., Manelli, I., Brautti, G., Ceshia, M. and Chersovani, L. Ibid., 1962,24, 876.CrossRefGoogle Scholar
  22. 21.
    Cocconi, G., Koester, L. J. and Perkins, D. H.The Barkeley High Energy Physics Study, UCRL-10022, 1961, pp. 167.Google Scholar
  23. 22.
    Malhotra, P. K...Nuc. Phys., 1964,59, 551.CrossRefGoogle Scholar
  24. 23.
    Willis, W. J., Fluery, P. both reported by Morrison, D. R. O. Sosnowski, R., reported by Morrison, D. R. O.C.E.R.N./T.C./Physics, 1963, 63–1.Google Scholar
  25. 24.
    Daniel, R. R., Kameswara Rao, N., Malhotra, P. K. and Tsuzuki, Y.Nuovo Cimento, 1960,16, 1.CrossRefGoogle Scholar
  26. 25.
    Belyakov, V. A., Wang Shu-Fen, Glagolev, V. V., Daljazhav, N., Lebedev, R. M., Mel’ Nikova, N. N., Nikitin, V. A., Petrazhilaka, V., Sviridov, V. A., Suk, M. and Tostov, E. D.Sov. Phys. J.E.T.P., 1960,39, 937;Ibid. 1961,12, 650.Google Scholar
  27. 26.
    Wang Shu-Fen, Visky, T., Gramanitskii, I. M., Girishin, V. G., Dalkhazan, N., Lebedev, R. M., Nomofilov, A. A., Podgoretskii, M. I. and Stel’Trov, V. N. Ibid., 1961,12, 663.Google Scholar
  28. 27.
    Ferbel, T. and Taft, H.Nuovo Cimento, 1963,28, 121.Google Scholar
  29. 28.
    Csejethey-Barth.. Ibid., 1964,32, 545.CrossRefGoogle Scholar
  30. 29.
    Goldsack, S. J., Riddiford, L., Tallini, B., French, B. R., Neale, W. W., Norbury, J. R., Skillicorn, I. O., Davies, W. T., Derrick, M., Mulvey, J. H. and Radogicic, D. Ibid., 1962,23, 941.CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 1967

Authors and Affiliations

  • T. N. Rengarajan
    • 1
  1. 1.Tata Institute of Fundamental ResearchBombay-5

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