Search for the ? decay of the narrow near-threshold proton resonance in 11B

Bottoni S. Corbari G. Leoni S. Fornal B. Goasduff A. Capra S. Mengoni D. Albanese E. Ziliani S. Benzoni G. Sánchez A.M. Bracco A. Brugnara D. Camera F. Ciemala M. Cieplicka-Orynczak N. Crespi F. Dueñas J.A. Gadea A. Galtarossa F. Gamba E. Gottardo A. Gozzelino A. Ha J. Iskra L.W. Marchi T. Menegazzo R. Million B. Napoli D.R. Pasqualato G. Pellumaj J. Perez-Vidal R. Pigliapoco S. Polettini M. Porzio C. Recchia F. Rezynkina K. Valiente Dobon J.J. Wieland O. Zanon I. Zhang G.
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Doi 10.1016/j.physletb.2024.138851
Volumen 855
2024-08-01
Citas: 1
Abstract
© 2024 The Author(s)The ? decay of the elusive narrow, near-threshold proton resonance in 11B was investigated at Laboratori Nazionali di Legnaro (INFN) in a particle-? coincidence experiment, using the 6Li(6Li,p?) fusion-evaporation reaction and the GALILEO-GALTRACE setup. No clear signature was found for a possible E1 decay to the 1/21?, first-excited state of 11B, predicted by the Shell Model Embedded in the Continuum (SMEC) with a branching of 0.98?69+167×10?3 with respect to the dominant particle-decaying modes. The statistical analysis of the ?-ray spectrum provided an average upper limit of 2.37×10?3 for this ?-ray branching, with a global significance of 5?. On the other hand, by imposing a global confidence level of 3?, a significant excess of counts was observed for E=?9300(20) keV, corresponding to a resonance energy of 11429(20) keV (namely 200(20) keV above the proton separation energy of 11B) and a ?-ray branching of 1.12(35)×10?3. This result is compatible with the SMEC calculations, potentially supporting the existence of a near-threshold proton resonance in 11B.
11B, Continuum shell model, Near-threshold resonance, ?-ray decay
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