Core exchange symmetries in heavy ion reactions

The general symmetry properties of the T-maxtrix due to the exchange of identical cores in nuclear reactions between composite particles are given. For the case of direct transfer reactions an explicit expression for the cross section is derived in the distorted wave Born approximation. In this model the cross section is the coherent sum of two indistinguishable transfer processes. The relative phase between the corresponding transfer amplitudes is obtained from the Pauli principle and depends on the signs of the spectroscopic amplitudes which may, therefore, be determined experimentally. (orig.)