The puzzle of the A2 meson
DOI: 10.1063/1.3021827
Particles in high‐energy physics have become so numerous that a new “resonance,” as a short‐lived unstable particle is called, must do something unusual to attract attention. The A2 meson, an otherwise ordinary resonance, stands out from the crowd by exhibiting a peculiar structure in its mass spectrum. Instead of the single peak of a normal resonance, the A2 has two closely spaced peaks with the separation between the peaks roughly equal to their width. This double peak implies that the A2 is really two particles with nearly the same mass, or perhaps a single object of an entirely new type, a double resonance or “dipole.”
References
1. A. R. Erwin and others, Phys. Rev. Lett. 6, 628 (1961).https://doi.org/PRLTAO
2. R. Baud, H. Benz, B. Bosňjaković, D. R. Botterill, G. Damgaard, M. N. Focacci, W. Kienzle, R. Klanner, C. Lechanoine, M. Martin, C. Nef, V. Roinishvili, P. Schübelin, A. Weitsch, H. Jöstlein, 2nd Philadelphia Conference on Meson Spectroscopy, May 1970.
3. G. Goldhaber and others, Phys. Rev. Lett. 12, 336 (1964).https://doi.org/PRLTAO
4. S. U. Chung and others, Phys. Rev Lett. 12, 621 (1964).
5. Aachen‐Berlin‐Birmingham‐Bonn‐Hamburg‐London (IC)‐Munich collaboration, Phys. Lett. 10, 226 (1964).https://doi.org/PHLTAM
6. S. U. Chung and others, UCRL 16881.
7. B. C. Maglić, G. Costa, Phys. Lett. 18, (1965).
8. B. Levrat, C. A. Tolstrup, P. Schübelin, C. Nef, M. Martin, B. C. Maglić, W. Kienzle, M. N. Focacci, L. Dubal, G. Chikovani, Phys. Lett. 22, 714 (1966).https://doi.org/PHLTAM
9. G. Chikovani, M. N. Focacci, W. Kienzle, C. Lechanoine, B. Levrat, B. C. Maglić, M. Martin, P. Schübelin, L. Dubal, M. Fischer, P. Grieder, C. Nef, Phys. Lett. 25B, 44 (1967).
10. G. Chikovani, G. Laverrière, P. Schübelin, Nucl. Instr. and Methods 47, 273 (1967).
11. M. L. Goldberger, K. M. Watson, Phys. Rev. 136B, 1472 (1964).
12. J. S. Bell, C. Goebel, Phys. Rev. 138B, 1198 (1965).https://doi.org/PHRVAO
13. H. Benz, G. E. Chikovani, G. Damgaard, M. N. Focacci, W. Kienzle, C. Lechanoine, M. Martin, C. Nef, P. Schübelin, R. Baud, B. Bosňjaković, J. Cotteron, R. Klanner, A. Weitsch, Phys. Lett. 28B, 233 (1968).
14. D. J. Crennel, U. Karshon, K. W. Lai, J. M. Scarr, I. O. Skillicorn, Phys. Rev. Lett. 20, 1318 (1968).https://doi.org/PRLTAO
15. M. Aguilar‐Benitez, J. Barlow, L. D. Jacobs, P. Malecki, L. Montanet, M. Tomas, M. Della‐Negra, J. Cohen‐Ganaouna, B. Lörstad, N. West, Phys. Lett. 29B, 62 (1969).
16. G. E. Chikovani, M. N. Focacci, W. Kienzle, U. Kruse, C. Lechanoine, M. Martin, P. Schübelin, Phys. Lett. 28B, 526 (1968).
17. R. A. Donald and others, Nucl. Phys. B12, 325 (1969).
18. K. Böckman and others, Bonn‐Durham‐Nijmegen‐Paris (EP)‐Torino collaboration, Nucl. Phys. B16, 221 (1970).
19. D. Cline, T. Buhl, Bull. Am. Phys. Soc. 15, no. 4, 513 (1970).
20. R. Baud, H. Benz, B. Bosňjaković, D. R. Botterill, G. Damgaard, M. N. Focacci, W. Kienzle, R. Klanner, C. Lechanoine, M. Martin, C. Nef, V. Roinishvili, P. Schübelin, A. Weitsch, H. Blumenfeld, H. Jöstlein, P. Lecomte, Phys. Lett. 31B, 397 (1970).
21. R. Baud, H. Benz, B. Bosňjaković, D. R. Botterill, G. Damagaard, M. N. Focacci, W. Kienzle, R. Klanner, C. Lechanoine, M. Martin, C. Nef, V. Roinishvili, P. Schübelin, A. Weitsch, H. Blumenfeld, H. Jöstlein, P. Lecomte, Phys. Lett. 31B, 401 (1970).
22. A. Barbaro‐Galtieri, S. E. Derenzo, S. M. Flatté, J. H. Friedman, M. A. Garnjost, G. R. Lynch, M. S. Rabin, F. T. Solmitz, F. Buhl, L. Epperson, S. Protopopescu, R. Ott (to be published).
23. R. C. Arnold, J. L. Uretsky, Phys. Rev. Lett. 23, 444 (1969).https://doi.org/PRLTAO
24. C. Rebbi, R. Slansky, Phys. Rev. 185, 1838 (1969).https://doi.org/PHRVAO
25. P. J. Davis, S. E. Derenzo, S. M. Flatté, M. A. Garnjost, G. R. Lynch, F. T. Solmitz, Phys. Rev. Lett. 23, 1071 (1969).https://doi.org/PRLTAO
More about the Authors
Peter Schübelin. Brookhaven National Laboratory.
