Particle decay of ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$

The particle decay of the ground state of ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$ was observed following population in the ${}_{}{}^6{}_{}{}^{}\mathrm{Li}({}_{}{}^3{}_{}{}^{}\mathrm{He}, t){}_{}{}^6{}_{}{}^{}\mathrm{Be}$ reaction. The $\alpha$ particle decay spectrum corresponds to the ordinary three body phase space shape for energies above about 100 keV in the ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$ center-of-mass system. At lower energies the relative yield exceeds the available phase space. It is shown that neither the phase space spectrum modified by the proton-proton final state interaction nor the spectrum corresponding to sequential decay through the ${}_{}{}^5{}_{}{}^{}\mathrm{Li}$ ground state have shapes consistent with the data. The enhanced yield of low energy $\alpha$ particles is not accounted for by either process.

RADIOACTIVITY ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$; measured $\sigma \left(E_{\alpha }\right)$. NUCLEAR REACTIONS ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$; ${}_{}{}^6{}_{}{}^{}\mathrm{Li}({}_{}{}^3{}_{}{}^{}\mathrm{He}, t){}_{}{}^6{}_{}{}^{}\mathrm{Be}\to \alpha +2p$, $E=24\mathrm{}$ MeV measured $E_t$, $E_{\alpha }$ coin.