An above-barrier narrow resonance in $^{15}$F
nucl-ex
/ Authors
F. De Grancey, A. Mercenne, F. de Oliveira Santos, T. Davinson, O. Sorlin, J. C. Angélique, M. Assié, E. Berthoumieux, R. Borcea, A. Buta
and 30 more authors
I. Celikovic, V. Chudoba, J. M. Daugas, G. Dumitru, M. Fadil, S. Grévy, J. Kiener, A. Lefebvre-Schuhl, N. Michel, J. Mrazek, F. Negoita, J. Okolowicz, D. Pantelica, M. G. Pellegriti, L. Perrot, M. Ploszajczak, G. Randisi, I. Ray, O. Roig, F. Rotaru, M. G. Saint Laurent, N. Smirnova, M. Stanoiu, I. Stefan
/ Abstract
Intense and purified radioactive beam of post-accelerated $^{14}$O was used to study the low-lying states in the unbound $^{15}$F nucleus. Exploiting resonant elastic scattering in inverse kinematics with a thick target, the second excited state, a resonance at E$\_R$=4.757(6)(10)~MeV with a width of $Γ$=36(5)(14)~keV was measured for the first time with high precision. The structure of this narrow above-barrier state in a nucleus located two neutrons beyond the proton drip line was investigated using the Gamow Shell Model in the coupled channel representation with a $^{12}$C core and three valence protons. It is found that it is an almost pure wave function of two quasi-bound protons in the $2s\_{1/2}$ shell.