Three-body approach to the multiple scattering direct reactions: Statistical theory of the continuum spectrum

The physical idea behind the present approach is that the ($a$,$\mathrm{ab}$) reaction continuum consists mainly of those particles $a$,$b$, following a quasifree knockout collision, which undergo an energy degradation due to rescattering on their way out from the target nucleus. The Feshbach, Kerman, and Koonin statistical two-body theory of the ($a$,$b$) reaction continuum is then extended to also describe this exclusive continuum process. A computable expression for the direct ($a$,$\mathrm{ab}$) continuum cross section is deduced as a convolution integral over a doorway quasifree cross section and a number of factors describing the probability of multiple rescattering of the quasifree particles on the residual nucleus. The resemblance between the two-body and the three-body expressions is remarkable and reflects their common physical support.