Heavy-Particle Stripping and the Structure ofN14

Abstract

A qualitative explanation is found for the interesting contrast observed between the angular distributions of the groups going to the ground state and the second excited state in the reaction ${\mathrm{C}}^{12}({\mathrm{Li}}^6, \alpha ){\mathrm{N}}^{14}$. The ground-state group of alphas has a peak only in the backward direction because only the mechanism of "heavy-particle stripping" can satisfy the requirements on the orbital angular momentum for the ground state of ${\mathrm{N}}^{14}$ (primarily a ${}_{}{}^3{}_{}{}^{}D$). The "deuteron" of the incident ${\mathrm{Li}}^6$ initially has insufficient angular momentum about the final core but acquires more because the force attracting it toward the target nucleus is not directed toward the center of mass of the twelve nucleons (eight from the target ${\mathrm{C}}^{12}$ and four from ${\mathrm{Li}}^6$) which form the core of the final ${\mathrm{N}}^{14}$. The other four nucleons from the target form the product alpha. The second excited state of ${\mathrm{N}}^{14}$ is approximately a ${}_{}{}^3{}_{}{}^{}S$ and there is no such angular momentum limitation so both light- and heavy-particle stripping occur and give rise to forward and backward peaks. The validity of the cluster model for ${\mathrm{Li}}^6$ is discussed.