Measurements of the differential cross sections for the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(d,ααn) reaction have been performed at deuteron incident energy E(d)=6.8 MeV. The kinematical configurations were chosen so as to optimize the population of the ${}_{}{}^5{}_{}{}^{}\mathrm{He}_{}^{\mathrm{*}\mathrm{*}}{}_{}{}^{}$ ${(3/2\mathrm{}}^{+}$ state with 16.76 MeV excitation energy. The parameters of this resonance are deduced from the experimental data; deviations from the standard values indicate the relevance of three-body effects and/or rescattering. Some phenomenological considerations give a qualitative explanation of the results obtained. In particular, as far as the width is concerned, we observe a broadening with respect to the standard value, which may be related to the presence of a shadow pole.

• Received 7 November 1988

DOI:https://doi.org/10.1103/PhysRevC.40.55