Quadrupole collectivity beyond N=28: Intermediate-energy Coulomb excitation of 47,48Ar

Abstract

We report on the first experimental study of quadrupole collectivity in the very neutron-rich nuclei \nuc{47,48}{Ar} using intermediate-energy Coulomb excitation. These nuclei are located along the path from doubly-magic Ca to collective S and Si isotopes, a critical region of shell evolution and structural change. The deduced $B(E2)$ transition strengths are confronted with large-scale shell-model calculations in the $sdpf$ shell using the state-of-the-art SDPF-U and EPQQM effective interactions. The comparison between experiment and theory indicates that a shell-model description of Ar isotopes around N=28 remains a challenge.

Accepted for publication in Physical Review Letters, typos fixed in resubmission on April 10

References in corpus (5)

• Nuclear magic numbers: new features far from stability
• Collapse of the N=28 shell closure in ${}^{42}$Si
• A new effective interaction for $0\hslash \omega$ shell model calculations in the sdpf valence space
• New isotope 44Si and systematics of the production cross sections of the most neutron-rich nuclei
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Cited by in corpus (3)

• Triaxial deformation and the loss of the N = 28 shell gap
• Examining the $N$ = 28 shell closure through high-precision mass measurements of ${}^{46-48}$Ar
• Low-lying 2${}^{+}$ states generated by $pn$-quadrupole correlation and $N=28$ shell quenching