Two well-separated particles

In scattering theory, one seeks to relate two well-defined situations, involving a scattered particle and a particle (or assembly of particles) which 

1 For readers interested in the cross connections between various theories, we note that the relation between K-matrix and Fano notations is also given explicitly in appendices to [377, 380). 

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The wavefunction for two well-separated particles has the general form ... 

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