Centre of mass motion and the Mott transition in light nuclei

Abstract

We calculate the effect of the inclusion of the centre of mass (CM) motion on the survival of light nuclear clusters in a vapour of nucleons at very low densities and moderate temperatures. The Mott transition refers to the dissolution of these clusters above a certain vapour density (the Mott density). The cluster CM motion has so far been included approximately or at fixed CM momentum in calculations of the Mott density. Often it is neglected altogether due to technical difficulties. In the present work we include the CM motion exactly for clusters up to A = 4 and calculate its effect by averaging over all values of the CM momentum at a given temperature rather than at a fixed value of the CM momentum. We demonstrate that the inclusion of the CM momentum shifts the Mott density to higher values. The shift, however, decreases as the cluster mass increases.