The existing experimental data on the d(n, p)nn and d(p, n)pp cross sections in the forward direction are reviewed in terms of the Dean sum rule. It is shown that the measurement of the ratio of the charge exchange on the deuteron to that on the proton might, if taken together with other experimental data, allow a direct construction of the np → np scattering amplitude in the backward direction with few ambiguities.
PACS. 13.75.Cs Nucleon nucleon interactions -25.40.Kv Charge-exchange reactions -25.10.+s Nuclear reactions involving few-nucleon systems 1 See Ref. [8] for a very comprehensive discussion of different amplitude bases.