The soft photon approximation (SPA), which is relativistic and based upon a fundamental theorem for photon emission, is applied to explore two separate nucleon-nucleon bremsstrahlung (NN) processes: pp and np. They are examined together in an effort to understand the mechanism which governs photon emission from these basic two-nucleon systems. In this investigation we focus upon the effect of the anomalous magnetic moments of the proton (p) and the neutron (n). In our SPA calculation we use the standard Low amplitude M as derived by Nyman plus the more recently developed amplitude M, referred to as the two-u-two-t special (TuTts) amplitude. The amplitude M is identical to the amplitude M through order K0 in the soft-photon expansion. However, M includes an additional term M(K1; ) (plus higher order terms). The term M(K1; ) is of order K1 in the soft-photon expansion and it is a function of p and n. Using the amplitudes M and M, we have calculated pp and np cross sections as a function of photon angle with and without contributions from p and n. Comparison with available pp data has been made; in particular, the contribution from M(K1; ) has been investigated. Results will be presented and discussed which relate to the following: (i) The anomalous magnetic moment effect is significant in pp; however, it is small in np. That is, the two amplitudes M and M yield very similar np cross sections, but they predict very different pp cross sections. (ii) M appears to provide a better SPA than M in the case of pp. Because p terms dominate the pp cross section, the contribution from M(K1; ) is important. Clearly, M(K1; ) makes a significant difference. (iii) The reason why M and M predict similar np cross sections will be analyzed and discussed.
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