Evaluation of finite range effects in distorted wave calculations of stripping and knock-out reactions

The six dimensional integrals that have to be evaluated in a full finite range DWBA calculation limits the number of partial waves that can be used in a computation. The proposed method, the radial matrix elements for the first few partial waves which are affected by the distortions were evaluated by a two dimensional integration; for higher partial waves, the matrix element was that obtained from a plane wave formulation. Since the plane wave matrix element can be computed analytically, it is possible using this prescription to include an infinite number of partial waves in DWBA calculations on stripping and knock-out reactions. Computations show that the inclusion of higher partial waves, normally neglected in standard codes, change the cross section by about 20%. (author)