DEPARTMENT OF NUCLEAR PHYSICS - NUCLEAR ENGINEERING - MEDICAL PHYSICS

Onset of collectivity for argon isotopes close to $N=32$

B. D. Linh et al.

Phys. Rev. C 109, 034312

Abstract:

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 $\gamma$ 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 $52\mathrm{Ca}$.

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