The meson exchange current contributions (MEC) to the ${}_{}{}^6{}_{}{}^{}\mathrm{He}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$${\to }^6$${\mathrm{Li}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ beta decay are computed for various nuclear amplitudes. We use particle-hole symmetry properties of one- and two-body matrix elements and find relationships between the A=6 beta decay and the anomalously suppressed ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$${\to }^{14}$${\mathrm{N}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ beta transition, for which these have been studied previously. We find MEC contributions to be small for the mass-six case, bringing the calculated axial vector form factor closer to the experimental value. Implications for the positive pion photoproduction transition between the same states are discussed.

• Received 5 July 1990

DOI:https://doi.org/10.1103/PhysRevC.42.1361