Wave Distortion for Magnetic Moment Effects in Nucleon-Nucleon Scattering

The paper is concerned with the difficulty of making reliable corrections for the effects of nucleonic magnetic moments on nucleon-nucleon scattering on account of the unknown effects of wave function distortion. A partial removal of the difficulty is accomplished by correcting for the magnetic moment effect only in the one-pion exchange (OPE) group of phase parameters. Wave-function distortion in that group is relatively small and the error committed is less serious than if the magnetic effects are used for the whole wave. Since the low L group has its phase parameters determined by adjustment to data, these parameters have to be interpreted as including the magnetic moment effects, which will eventually have to be corrected for, when the origin of the nucleon-nucleon phase shifts is understood quantitatively in other respects. Formulas for the calculation of the magnetic moment effects in the high L group are supplied and some typical cases are considered numerically. Relatively large effects are found for the polarization P and, literally speaking, the triple-scattering parameter A at very small angles. The complication arising in n-p data analysis from coupling of states with different isotopic spin is pointed out.