A kinematically complete experiment has been performed to study the deuteron breakup by $\alpha$ particles at six incident energies between $E_{\alpha }=9.735\mathrm{}$ and $E_{\alpha }=11.30\mathrm{}$ MeV (3.245 to 3.77 MeV in c.m.), very close to threshold. The data show strong energy dependence. Final-state calculations with the $\alpha p$ and $\alpha n$ interactions provide only fair fits, but the addition of three-body forces produces a significant improvement.

NUCLEAR REACTIONS ${}_{}{}^2{}_{}{}^{}\mathrm{H}(\alpha , p\alpha )n$, $E=9.735\mathrm{} \mathrm{to} 11.30$ MeV; measured $\sigma (E_p, {\theta }_p, {\theta }_{\alpha })$: gas target.

• Received 29 February 1980

DOI:https://doi.org/10.1103/PhysRevC.22.1815