Ne 20 ( α , 2 α ) O 16 reaction at 78.6 MeV

The $^{20}\mathrm{Ne}(\ensuremath{\alpha},2\ensuremath{\alpha})^{16}\mathrm{O}$ reaction has been measured at symmetric and asymmetric sets of angles at ${E}_{\ensuremath{\alpha}}=78.6$ MeV. The data indicate that quasifree $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\alpha}$ scattering and, consequently, $\ensuremath{\alpha}$ clustering plays a dominant role for pairs of angles favoring quasifree scattering. The data have been compared with the plane-wave impulse approximation using a radial cutoff. This calculation does not give a good fit to data for non-quasifree angles. The reaction goes predominantly to the $^{16}\mathrm{O}$ ground state with a small yield to the 6.92-7.12-MeV doublet in $^{16}\mathrm{O}$.[NUCLEAR REACTIONS $^{20}\mathrm{Ne}(\ensuremath{\alpha},2\ensuremath{\alpha})^{16}\mathrm{O}$, $E=78.6$ MeV; measured (${E}_{L},{E}_{R},{\ensuremath{\theta}}_{L},{\ensuremath{\theta}}_{R}$). PWIA analysis.]