Onset of collectivity for argon isotopes close to N=32

Le résumé fourni par la source

The shell closure at $N=32$ has been investigated by a first spectroscopy of the $N=31$ nucleus $^{49}\mathrm{Ar}$ at the Radioactive Isotope Beam Factory. Using the $^{50}\mathrm{Ar}(p,pn)$ reaction channel in inverse kinematics, $^{50}\mathrm{Ar}$ projectiles at 217 MeV/nucleon impinged on a 150 mm long liquid hydrogen target, part of the MINOS device. Prompt deexcitation $\ensuremath{\gamma}$ rays were measured with the NaI(Tl) array ${\mathrm{DALI}2}^{+}$. Reaction products were analyzed with the SAMURAI spectrometer, which allowed the measurement of the momentum distributions and angular momentum transfer. Data were compared to state-of-the-art theoretical predictions, including shell-model, energy-density functional, and ab initio calculations. An onset of collectivity is suggested besides the spherical configuration typical of a closed shell nucleus, such as for $^{52}\mathrm{Ca}$.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.