Abstract
Positron and electron beams from the Stanford Mark III linear accelerator have been used to investigate the importance of two-photon exchanges in electron scattering from the proton. The scattering cross sections for positrons and electrons have been compared at 200 and 300 MeV for (the square of the four-momentum transfer) from 0.3 to 5.2 . The results show no evidence of anomalous two-photon effects and verify the correctness of the first Born approximation form factor analysis to within a few percent or better for this range of . The variation of the cross sections with has also been measured with high accuracy.
The specific ionizations of 300-MeV positrons and electrons in hydrogen at one atmosphere have been compared in the course of the experiment, and found to be equal to within ±0.3%.
- Received 25 June 1962
DOI:https://doi.org/10.1103/PhysRev.128.1842
©1962 American Physical Society