β-delayed proton emission from 11Be in effective field theory

We calculate the rate of the rare decay Be-11 into Be-10 + p + e(-) + (nu) over bar (e) using Halo effective field theory, thereby describing the process of beta-delayed proton emission. We assume a shallow 1/2(+) resonance in the Be-10-p system with an energy consistent with a recent experiment by Ayyad et al. and obtain b(p) = 4.9(-2.9)(+5.6)(exp.)(-0.8)(+4.0)(theo.) x 10(-6) for the branching ratio of this decay, predicting a resonance width of Gamma(R) = (9.0(-3.3)(+4.8)(exp.)(-2.2)(+5.3)(theo.)) keV. Our calculation shows that the experimental branching ratio and resonance parameters of Ayyad et al. are consistent with each other. Moreover, we analyze the general impact of a resonance on the branching ratio and demonstrate that a wide range of combinations of resonance energies and widths can reproduce branching ratios of the correct order. Thus, no exotic mechanism (such as beyond the standard model physics) is needed to explain the experimental decay rate. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

The research team calculated the rate of the rare decay Be-11 into Be-10 + p + e(-) + (nu) over bar (e) using Halo effective field theory to describe beta-delayed proton emission. They assumed a resonance in the Be-10-p system consistent with a recent experiment, obtaining a branching ratio and predicting a resonance width. The experimental results and resonance parameters were found to be consistent, and it was demonstrated that no exotic mechanisms are needed to explain the experimental decay rate.