Si29,30(O16,N15) proton stripping reaction at 60 MeV

Abstract

Differential cross sections of the [$^{16}\mathrm{O}$, $^{15}\mathrm{N}$(g.s.)] reaction on $^{29}\mathrm{Si}$ and $^{30}\mathrm{Si}$ were measured at $E(^{16}\mathrm{O})=60$ MeV at far forward angles. The strongly oscillatory $\ensuremath{\Delta}L=1$, (2) angular distributions for the $2{s}_{\frac{1}{2}}$ and $1{d}_{\frac{3}{2}}$ transitions to $^{30}\mathrm{P}$ and $^{31}\mathrm{P}$ were found to be out of phase. The pure $\ensuremath{\Delta}L=1$, $2{s}_{\frac{1}{2}}$ transitions were fitted well by finite range distorted wave Born approximation calculations using the code LOLA. The phase of the structure of the $1{d}_{\frac{3}{2}}$ transfer angular distributions could not be fitted with the distorted wave Born approximation. Spectroscopic factors were in good agreement with ($^{3}\mathrm{He},d$) results for $2{s}_{\frac{1}{2}}$ and $1{d}_{\frac{5}{2}}$ transitions and a factor of 2 too large for $1{d}_{\frac{3}{2}}$ transfer. This factor of 2 for the $1{d}_{\frac{3}{2}}$ transitions is not understood. The mixed $j$ transition to the ${2}^{+}$ state in $^{30}\mathrm{P}$ (1.454 MeV) was found to be consistent with almost exclusive $j=\frac{3}{2}$ transfer as predicted by shell model calculations.NUCLEAR REACTIONS $^{29,30}\mathrm{Si}$($^{16}\mathrm{O}$, $^{15}\mathrm{N}$), $E=60$ MeV; measured $\ensuremath{\sigma}({E}_{15N},\ensuremath{\theta})$, deduced ${C}^{2}{S}_{lj}$.