Large longitudinal spin alignment generated in inelastic nuclear reactions

Abstract

Large longitudinal spin alignment of $E/A=24\phantom{\rule{0.16em}{0ex}}\mathrm{MeV}\phantom{\rule{4pt}{0ex}}^{7}\mathrm{Li}$ projectiles inelastically excited by Be, C, and Al targets was observed when the latter remain in their ground state. This alignment is a consequence of an angular-momentum-excitation-energy mismatch, which is well described by a DWBA cluster-model ($\ensuremath{\alpha}+t$). The longitudinal alignment of several other systems is also well described by DWBA calculations, including one where a cluster model is inappropriate, demonstrating that the alignment mechanism is a more general phenomenon. Predictions are made for inelastic excitation of $^{12}\mathrm{C}$ for beam energies above and below the mismatch threshold.