Isospin-forbidden d1 production in the 4He(d,pαn reaction with tensor-polarized beam

The ${}^4\text{He}\text{(}\text{d}\text{,}\text{p}\text{α)}\text{n}$ reaction has been studied in a kinematically complete experiment using a tensor-polarized deuteron beam to investigate the isospin-forbidden pn final-state interaction. A clear dependence of the cross section near E_pn = 0 on the spin state of the incoming deuterons has been found as expected if the bumps observed by several authors at small pn relative energies are indeed due to the isospin-forbidden proton-neutron FSI in the ¹S₀, T = 1 state.