Direct Observation of Proton Emission in $^{11}\mathrm{Be}$

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Direct Observation of Proton Emission in ${}^{11}{Be}$

Y. Ayyad et al.

Phys. Rev. Lett. 123, 082501 – Published 22 August 2019; Erratum Phys. Rev. Lett. 124, 129902 (2020)

Abstract

The elusive $β^{-} p^{+}$ decay was observed in ${}^{11}{Be}$ by directly measuring the emitted protons and their energy distribution for the first time with the prototype Active Target Time Projection Chamber in an experiment performed at ISAC-TRIUMF. The measured $β^{-} p^{+}$ branching ratio is orders of magnitude larger than any previous theoretical model predicted. This can be explained by the presence of a narrow resonance in ${}^{11}B$ above the proton separation energy.