Influence of D-state in ⁴He on S Factor for the ²H(d,γ)⁴He Reaction

We employ a direct capture method to study the influence of D-state in ⁴He on S factor for the ²H(d,γ)⁴He reaction, in which the D-state component of the colliding deuterons and D-state component in ⁴He ground state are considered. The parameters of Woods--Saxon (WS) potentials are obtained by reproducing the binding energy of d--d (i.e. ²H--²H) system, and d--d elastic scattering phase shifts calculated by the resonating group method. The theoretical results are in good agreement with the experimental data at E_c.m < 3MeV. The impact of the D state probability in ⁴He on the extrapolated value of the astrophysical S factor for ²H(d,γ)⁴He reaction is discussed.