Li6+N15 interaction at Ec.m.=23.1 MeV : Validation of the α+d cluster model of Li6

Abstract

An extensive data set for the $^{6}\mathrm{Li}+^{15}\mathrm{N}$ system at an energy ${E}_{\mathrm{c}.\mathrm{m}.}=23.1$ MeV, consisting of elastic and inelastic scattering to excited states of $^{15}\mathrm{N}$ and the ${3}_{1}^{+}$, ${2}_{1}^{+}$, and ${1}_{1}^{+}$ spin-orbit triplet of $L=2$, $T=0$ resonances in $^{6}\mathrm{Li}$, was analyzed with a single calculation including the $^{6}\mathrm{Li}\ensuremath{\rightarrow}\ensuremath{\alpha}+d$ breakup, excitation of the $^{15}\mathrm{N}$ levels, and the $^{15}\mathrm{N}(^{6}\mathrm{Li},^{7}\mathrm{Li})^{14}\mathrm{N}$ one-neutron pickup reaction employing the coupled discretized continuum channel, coupled channel, and coupled reaction channel techniques, respectively. Since the experiment was performed in inverse kinematics, and owing to the specific structure properties of $^{15}\mathrm{N}$, it was possible to measure an angular distribution for population of the ${1}_{1}^{+}$ resonance of $^{6}\mathrm{Li}$ for the first time, without the need for time-consuming and complicated coincidence measurements through detection of the scattered $^{15}\mathrm{N}$. A good description of the cross sections for populating all three $^{6}\mathrm{Li}$ resonances was obtained, confirming the validity of the $\ensuremath{\alpha}+d$ cluster model of $^{6}\mathrm{Li}$. In the methodology adopted the surface absorption was mostly generated by the included couplings, and while the $^{6}\mathrm{Li}$ breakup had the most important influence on the elastic scattering, coupling to the $^{15}\mathrm{N}$ inelastic excitations was also found to have a significant effect, particularly at midrange angles. By contrast, the one-neutron pickup coupling had a negligible effect on the other channels.