1. incident π−:W. D. Walker, R. Hushfar andW. D. Shephard:Phys. Rev.,104, 526 (1956);E. Eisberg et al.:Phys. Rev.,97, 797 (1955);W. D. Walker andJ. Crussard:Phys. Rev.,98, 1416 (1955). The Fig. 20 in this paper contains one of the distributions which we shall discuss below. It is the only example we know.
2. incident p:T. W. Morris et al.:Phys. Rev.,103, 1472 (1956);W. B. Fowler et al.: Phys. Rev.,103, 1479 (1956);W. B. Fowler et al.: Phys. Rev.,103, 1489 (1956);M. M. Block et al.: Phys. Rev.,103, 1484 (1956).
3. J. Sellen, G. Cocconi, V. T. Cocconi andE. Hart:Phys. Rev.,110, 779 (1958).
4. For a discussion of the isobaric model compare:S. J. Lindenbaum andR. M. Sternheimer:Phys. Rev.,109, 1722 (1958) for the case of reaction (1) andPhys. Rev.,105, 1874 (1957) for the case of the reaction N+N→→N+N+π. Our point of view is however somewhat different from that expressed in the above mentioned papers; our question is simply to know whether considering only that subclass of events, which, kinematically could be compatible with the isobaric model, the relative angular momentum of the pion and nucleon from the « decay » of the isobaric state is 3/2 as it should be; of course it is to be hoped that the subclass of events in question is an appreciable fraction of the total number of the events; it is however difficult to say at present how appreciable it is and the experimental data do not furnish a clear picture.
5. CompareD. H. Wilkinson:Phys. Rev.,109, 1603, 1610, 1613 (1958) and the references quoted there.