New ab initio approach for nuclear reactions*

I will discuss a new ab initio approach for nuclear reactions involving nuclei up to the medium-mass region. This approach is based on the \textit{ab initio} symmetry-adapted framework combined with the resonating group method (RGM). It follows the same concept that has been successfully applied to \textit{ab initio} reactions of light nuclei, but now we take advantage of the SU(3) symmetry. This new feature enables a reorganization of the large-scale model space into physically relevant basis states and paves the way to \textit{ab initio} reactions involving heavier and more exotic nuclei of astrophysical interest. In particular, the nuclear structure of the target is described with the \textit{ab initio} symmetry-adapted no-core shell model, and the target-projectile composite system is described within an SU(3) RGM framework. I will discuss the underlying formalism, which involves the expressions of the norm and Hamiltonian kernels in an SU(3) basis, along with the first applications of the model to one-nucleon projectile reactions. The computational efficacy of the reaction model will be illustrated for a ${}^{20}$Ne target.