Variational Monte Carlo calculations of the 2H(d, gamma )4He reaction at low energies.

Abstract

The $^{2}\mathrm{H}$(d,\ensuremath{\gamma}${)}^{4}$He reaction is studied at center-of-mass energies below 500 keV, where it is dominated by the E2 transition from the $^{5}$${\mathit{S}}_{2}$ continuum state to the ground state of the \ensuremath{\alpha} particle. Both the $^{5}$${\mathit{S}}_{2}$ continuum and the ground states are calculated with the variational Monte Carlo method using the realistic Argonne-${\mathit{v}}_{14}$ two-nucleon and Urbana model-VII three-nucleon interactions. A qualitative agreement with the observed cross section is obtained. This reaction can proceed only through the D states in the deuteron and/or in the \ensuremath{\alpha} particle. It is found that, depending upon the continuum wave function, the contributions of the deuteron and \ensuremath{\alpha}-particle D states can either add to produce a large cross section, or cancel. The reaction is thus very sensitive to the continuum wave function.