The near-threshold proton resonance in ${}^{11}\mathrm{B}$, recently identified and characterized through independent experiments, plays a crucial role in understanding the unexpectedly high decay branch observed in the $\beta$-delayed proton emission (${\beta }^{-}p$) from the neutron halo nucleus ${}^{11}\mathrm{Be}$. Critical to interpreting this process is the determination of whether or not this state has any significant $\alpha$-decay width (${\mathrm{\Gamma }}_{\alpha }$). A coincidence measurement was conducted to study the alpha-transfer reaction ${}^7\mathrm{Li}({}^7\mathrm{Li}, t){}^{11}\mathrm{B}^{*}\to {}^7\mathrm{Li}+\alpha$ employing the Super-Enge Split Pole Spectrograph coupled with a silicon detector at Florida State University. This experiment aimed to investigate the structure of $\alpha$ resonances in ${}^{11}\mathrm{B}$ in the $E_{\mathrm{ex}}=9.0$ MeV–14 MeV energy region. In particular, to explore and constrain the $\alpha$-decay branch of the near-threshold proton resonance at $E_{\mathrm{ex}}=11.44$ MeV. No significant $\alpha$-decay strength was observed from this state. Additionally, the experimental results provided insights into the state at $E_{\mathrm{ex}}=12.55$ MeV, previously proposed as the T = 3/2 isobaric analog state of the ${}^{11}\mathrm{Be}$ ground state. The observed decay pattern, dominated by $\alpha +{}^7\mathrm{Li}$, suggests a strong T = 1/2 component, indicating the need for further experimental measurements.

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• Alpha decay
• Nuclear structure & decays
• Resonance reactions
• Transfer reactions
• 6 ≤ A ≤ 19