$\beta$-delayed proton emission from ${}^{11}$Be in effective field theory

Abstract

We calculate the rate of the rare decay ${}^{11}\text{Be}$ into ${}^{10}\text{Be}+p+e^{-}+{\bar{\nu }}_e$ using Halo effective field theory, thereby describing the process of beta-delayed proton emission. We assume a shallow $1/2^{+}$ resonance in the ${}^{10}\text{Be}-p$ system with an energy consistent with a recent experiment by Ayyad et al. and obtain $b_p=4.9_{-2.9}^{+5.6}{\text{(exp.)}}_{-0.8}^{+4.0}\text{(theo.)}\times 10^{-6}$ for the branching ratio of this decay, predicting a resonance width of ${\Gamma }_R=(9.0_{-3.3}^{+4.8}{\text{(exp.)}}_{-2.2}^{+5.3}\text{(theo.)})\text{keV}$. 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.

7 pages, 4 figures; discussion expanded, accepted for publication in Phys. Lett. B

References in corpus (14)

• alpha-alpha Scattering in Halo Effective Field Theory
• Halos and related structures
• Radiative Neutron Capture on Lithium-7
• Dark Side of the Neutron?
• Direct observation of proton emission in 11Be
• Convenient location of a near-threshold proton-emitting resonance in ${}^{11}$B
• Rare $\beta$p decays in light nuclei
• Constraining Low-Energy Proton Capture on Beryllium-7 through Charge Radius Measurements
• Search for beta-delayed proton emission from ${}^{11}$Be
• Clarification of large-strength transitions in the beta decay of 11Be
• Low-energy bound states, resonances, and scattering of light ions
• Universal physics of bound states of a few charged particles
• Neutron transfer reactions in halo effective field theory
• Comment on "Direct Observation of Proton Emission in ${}^{11}$Be"

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• ${\beta }^{-}\mathrm{p}$ and ${\beta }^{-}\alpha$ decay of the ${}^{11}$Be neutron halo ground state
• Single-particle properties of the near-threshold proton-emitting resonance in ${}^{11}$B
• Final-state interactions and spin structure in $E1$ breakup of ${}^{1}1$Li in Halo EFT
• Weak decay of halo nuclei