Summary
A search for four-pion resonances among six-prong annihilations of 1.61 GeV/c antiprotons in the Berkeley 72 in. hydrogen bubble chamber has been made. No four-body decays of the ρ or ω mesons have been observed and upper limits for these decays are quoted. The fraction of the charged ρ mesons which decay via ρ±→η+π± is determined to be (1.2±2)%, in agreement with a positiveG parity assignment for the η. The neutral four-pion effective mass distribution shows a suggestive, but inconclusive, peak at 1.04 GeV.
Riassunto
Si sono ricercate la risonanze a quattro pioni fra le annichilazioni a sei rami degli antiprotoni di 1.61 GeV/c nella camera a bolle a idrogeno da 72 in. di Berkeley. Non si sono notati decadimenti a quattro corpi dei mesoni ρ od ω e si danno i limiti superiori per questi decadimenti. Si è determinato che la frazione di mesoni ρ carichi, che decadono via ρ±→η+π±, è (1.2±2)%, in accordo con l’assegnazione di una paritàG positiva all’η. La distribuzione della massa effettiva del quadripione neutro presenta un picco suggestivo, ma inconcludente, a 1.04 GeV.
Similar content being viewed by others
References
A. R. Erwin, R. March, W. D. Walker andE. West:Phys. Rev. Lett.,6, 628 (1961);E. Pickup, D. K. Robinson andE. W. Salant:Phys. Rev. Lett.,7, 192 (1961);D. Carmony andR. Van de Walle:Phys. Rev. Lett.,8, 73 (1962);J. Button, G. R. Kalbfleisch, G. R. Lynch, B. C. Maglić, A. H. Rosenfeld andM. L. Stevenson:Phys. Rev.,121, 1788 (1961).
B. C. Maglić, L. W. Alvarez, A. H. Rosenfeld andM. L. Stevenson:Phys. Rev. Lett.,7, 178 (1961);N. H. Xuong andG. R. Lynch:Phys. Rev. Lett.,7, 327 (1961).
A. Pevsner, R. Kraemer, M. Nussbaum, C. Richardson, P. Schlein, R. Strand, T. Toohig, M. Block, A. Engler, R. Gessaroli andC. Meltser:Phys. Rev. Lett.,7, 421 (1961);P. Bastien, J. P. Berge, O. I. Dahl, M. Ferro-Luzzi, D. H. Miller, J. J. Murray, A. H. Rosenfeld andM. B. Watson:Phys. Rev. Lett.,8, 114 (1962);D. C. Carmony, A. H. Rosenfeld, andR. Van de Walle:Phys. Rev. Lett.,8, 117 (1962).
G. F. Chew andS. C. Frautschi:Phys. Rev. Lett.,8, 41 (1962);G. F. Chew andS. C. Frautschi:Phys. Rev. Lett.,7, 395 (1961). This resonance was first predicted byC. Loveless, but at an energy of about 400 MeV (to be published).
M. Ikeda, S. Ogawa andY. Ohnuki:Progr. Theor. Phys. Kyoto,22, 715 (1959);Y. Ohnuki: inProc. of the 1960 Annual International Conference on High-Energy Physics at Rochester (New York, 1960);Y. Yamaguchi:Progr. Theoret. Phys. Kyoto, Suppl., No 11 (1959);J. Wess:Nuovo Cimento,10, 15 (1960);S. Minami:Heavy mesons and hard core in Nuclear Force, preprint (Osaka University);M. Gell-Mann:Symmetries of baryons and mesons, inPhys. Rev. (to be published).
M. L. Stevenson, L. W. Alvarez, B. C. Maglić andA. H. Rosenfeld:Phys. Rev.,125, 687 (1962);N. H. Xuong andG. R. Lynch:Phys. Rev. Lett.,7, 327 (1961).
H. P. Duerr andW. Heisenberg:Nuovo Cimento,23, 807 (1962).
G. Feinberg is the first one to mention the ρ→π+η decay;Phys. Rev. Lett.,8, 151 (1962).
J. Button, P. Eberhard, G. R. Kalbfleisch, J. E. Lannutti, G. R. Lynch, B. C. Maglić, M. L. Stevenson andN. H. Xuong:Phys. Rev.,121, 1788 (1961).
R. E. Foulks: (Lawrence Radiation Laboratory), private communication.
A. H. Rosenfeld, D. Carmony andR. Van de Walle:Phys. Rev. Lett.,8, 293 (1962).
Author information
Authors and Affiliations
Additional information
Work done under the auspices of the U.S. Atomic Energy Commission.
Rights and permissions
About this article
Cite this article
Xuong, NH., Lynch, G.R. Search for a four-pion resonance, and some decay modes of the ρ and ω-mesons. Nuovo Cim 25, 923–930 (1962). https://doi.org/10.1007/BF02733158
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02733158