Summary
The one-pion-exchange model of pion photoproduction from protons is considered at high energy. To eliminate the unknown γπ interaction, the double and triple photoproduction processes are considered simultaneously in a restricted region of the phase-space. The appropriately defined ratios of their differential cross-sections represent the ratios of theN * «production» to that ofN. These ratios are computed for several incident-photon energies.
Riassunto
Si studia, alle alte energie, in modello a scambio di un pione per la fotoproduzione di pioni da protoni. Per eliminare l’incognita interazione γπ, si studiano, simultaneamente in una ristretta regione dello spazio delle fasi, i processi di fotoproduzione doppia e tripla. I rapporti opportunamente definiti delle loro sezioni d’urto differenziali rappresentano i rapporti fra la «produzione» diN * e quella diN. Si calcolano questi rapporti per numerosi valori dell’energia del fotone incidente.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
See, for instance,E. Ferrari andF. Selleri:Suppl. Nuovo Cimento,24, 453 (1962);Nuovo Cimento,27, 1450 (1963), where other references are also given. One should remark that a simple peripheral calculation done in the standard manner is not always able to explain the observed facts. In this connection, seeM. M. Islam:Phys. Rev.,131, 2292 (1963).
F. R. Arutyunyan andV. A. Tumanyan:Soviet Physics JETP,17, 1412 (1963). See alsoF. R. Arutyunyan, I. I. Gol’dman andV. A. Tumanyan:Soviet Physics JETP 18, 218 (1964).
G. F. Chew andF. E. Low:Phys. Rev.,113, 1640 (1959).
F. Salzman andG. Salzman:Phys. Rev.,120, 599 (1960).
The experimentalists are not unfamiliar with kinematical restrictions of this type. In fact, the evidence for a π-π resonance (ρ-meson) from double-pion photo-production was obtained in this fashion. SeeD. McLeod, S. Richert andA. Silverman:Phys. Rev. Lett.,7, 383 (1961).
In addition to the ref. (1,3,4), seeS. D. Drell:Rev. Mod. Phys.,33, 458 (1961);M. S. K. Razmi:Nuovo Cimento,31, 615 (1964), and a host of other people. Notice, however, that the expressions given by these authors are for πN andNN collisions. A few minor modifications are required here and there for our case.
E. Ferrari andF. Selleri:Nuovo Cimento,21, 1028 (1961). The derivation of eq. (15) depends on the following assumptions: 1) one-dimensional dispersion relations in the energy variable can be written down for suitably defined invariant amplitudes of the pion-nucleon scattering; 2) dispersion integrals in the off-shell case are dominated byT=J=3/2 amplitude and 3) magnitude of the squared four-momentum of the virtual pion is ≲ 5µ2.
N. P. Klepikov, V. A. Meshcheryakov andS. N. Sokolov: Dubna Report D., 584 (1960).
I am much in debt toC. Lovelace andP. Auvil for providing me with the data referred to and for several clarifications.
P. Bareyre, C. Bricman, G. Valladas, G. Villet, J. Bizard andJ. Seguinot:Phys. Lett.,8, 137 (1964).
Author information
Authors and Affiliations
Additional information
The Research reported in this document has been sponsored in part by the Air Force Office of Scientific Research OAR through the European Office Aerospace Research, United States Air Force.
The computations were done on the Elliot Computer of the Physics Department for which the author is obliged toF. Campayne andZ. Ahmed.
Rights and permissions
About this article
Cite this article
Razmi, M.S.K. On double and triple photoproduction of pions. Nuovo Cim 34, 150–162 (1964). https://doi.org/10.1007/BF02725876
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF02725876