$\beta^-{\rm p}$ and $\beta^-\alpha$ decay of the $^{11}$Be neutron halo ground state

Beta-delayed proton emission from the neutron halo ground state of $^{11}$Be raised much attention due to the unusually high decay rate. It was argued that this may be due to the existence of a resonance just above the proton decay threshold. In this Letter, we use the lenses of real-energy continuum shell model to describe several observables including the Gamow-Teller rates for the $\beta^-$-delayed $\alpha$ and proton decays, and argue that, within our model, the large $\beta^-{\rm p}$ branching ratio cannot be reconciled with other data.
Comment: 5 pages, 3 figures