Mechanism of the(6Li,He6) reaction at intermediate energies and its suitability as a spin probe

Angular distributions have been measured for the ${(}^6$Li, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$) reaction on targets of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{12}{}_{}{}^{}$,14C, ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ at bombarding energies of 35, 25, and 14 MeV/nucleon. The ratios of observed cross sections for states in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ suggest that the reaction mechanism is predominantly one-step at 35 and 25 MeV/nucleon with an increasing contribution from sequential transfer at lower energies. Measured forward-angle cross sections for Gamow-Teller transitions are found to be accurately proportional to the corresponding B(GT) values from ${\beta }^{\mathrm{-}}$ decay or from (p,n) data. This calibration will allow the measurement of spin-transfer strength with the ${(}^6$Li, ${}_{}{}^6{}_{}{}^{}\mathrm{He}$) reaction at intermediate energies. One-step distorted-wave Born approximation calculations, which used Yukawa central and $r^2$× Yukawa tensor potentials, are consistent with the data at 35 and 25 MeV/nucleon except for ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}<3\mathrm{}}$°, and give a central force strength, $V_{\sigma \tau }$, in reasonable agreement with that obtained in (p,n) studies at similar energies per nucleon.