THE EFFECT OF RECOIL ON THE SCATTERING OF μ-MESONS BY LIGHT NUCLEI

The correction of the recoil to the potential in the scattering of μ-mesons (or electrons) by zero-spin nuclei is derived by means of a simple method. The potential obtained is corrected to first order in the velocity of the nuclei but without restriction on the velocity of the μ-mesons (or electrons). The effect of recoil on the phase-shift and cross section is discussed. The results are compared with those of Foldy, Ford and Yennie. It is pointed out that the method used in the latter's work is not perfect, because it makes use of Breit's interaction which is valid only for small velocities.