Evidence of a Near-Threshold Resonance in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi mathvariant="normal">B</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math> Relevant to the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>β</mml:mi></mml:math>-Delayed Proton Emission of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Be</mml:mi></mml:mrow><mml:mprescripts/><mml:none/><mml:mrow><mml:mn>11</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>
Y. Ayyad, W. Mittig, Tao Tang, B. Olaizola, G. Potel, N. Rijal, N. Watwood, H. Álvarez-Pol, D. Bazin, M. Caamaño, J. Chen, M. Cortesi, B. Fernández–Domínguez, S. Giraud, P. Guèye, S. Heinitz, R. Jain, B. P. Kay, E. A. Maugeri, B. Monteagudo, F. Ndayisabye, S. N. Paneru, Jorge Pereira, E. Rubino, C. Santamaria, D. Schumann, J. Surbrook, Louis K. Wagner, J. C. Zamora, Vladimir Zelevinsky
Abstract
A narrow near-threshold proton-emitting resonance (${E}_{x}=11.4\text{ }\text{ }\mathrm{MeV}$, ${J}^{\ensuremath{\pi}}=1/{2}^{+}$, and ${\mathrm{\ensuremath{\Gamma}}}_{p}=4.4\text{ }\text{ }\mathrm{keV}$) was directly observed in $^{11}\mathrm{B}$ via proton resonance scattering. This resonance was previously inferred in the $\ensuremath{\beta}$-delayed proton emission of the neutron halo nucleus $^{11}\mathrm{Be}$. The good agreement between both experimental results serves as a ground to confirm the existence of such exotic decay and the particular behavior of weakly bound nuclei coupled to the continuum. $R$-matrix analysis shows a sizable partial decay width for both, proton and $\ensuremath{\alpha}$ (${\mathrm{\ensuremath{\Gamma}}}_{\ensuremath{\alpha}}=11\text{ }\text{ }\mathrm{keV}$) emission channels.