Il Nuovo Cimento (1955-1965)

, Volume 30, Issue 6, pp 1396–1405 | Cite as

Higher-order calculation of the electron-pair production cross-section

  • D. S. Moroi
  • C. L. Hammer


The pair production cross-section is calculated to order α3Z3 for the case where the incident photon and one of the electrons have an energy much greater thanmc2. Comparison of these calculations to the experimental data of Plimpton and Hammer shows an improvement in agreement between theory and experiment of approximately a factor of l + (αZ4π/15) for low positron kinetic energies. However, for positron kinetic energies of the order of 1 MeV no improvement is obtained. In addition it is shown for large-angle emission of the positron (electron) that the Bethe-Heitler cross-section multiplied by the Coulomb factor gives the correct cross-section to lowest order in αZ.


Si calcola la sezione d’urto per la produzione di coppie sino all’ordineα3Z3 per il caso in oui il protone incidente ed uno degli elettroni hanno un’energia molto maggiore dimc2. II confronto di questi calcoli con i dati sperimentali di Plimpton ed Hammer indica un miglioramento nella concordanza fra teoria ed esperimento per un fattore di 1+(αZ4π/15) a basse energie cinetiche del positone. Invece, ad energie cinetiche del positone dell’ordine di 1 MeV non si ottiene alcun miglioramento. Inoltre si mostra che, a grandi angoli di emissione del positone (elettrone), la sezione d’urto di Bethe-Heitler moltiplicata per il fattore di Coulomb dà la sezione d’urto corretta sino all’ordine più basso di αZ.


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Copyright information

© Società Italiana di Fisica 1963

Authors and Affiliations

  • D. S. Moroi
    • 1
  • C. L. Hammer
    • 1
  1. 1.Institute for Atomic Research and Department of PhysicsIowa State UniversityAmes

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