Pairing-quadrupole interplay in the neutron-deficient tin nuclei: first lifetime measurements of low-lying states in ${}^{106,108}$Sn

Abstract

The lifetimes of the low-lying excited states $2^{+}$ and $4^{+}$ have been directly measured in the neutron-deficient ${}^{106,108}$Sn isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted $\gamma$ rays were detected by the AGATA array, while the reaction products were uniquely identified by the VAMOS++ magnetic spectrometer. Large-Scale Shell-Model calculations with realistic forces indicate that, independently of the pairing content of the interaction, the quadrupole force is dominant in the $B(E2;2_1^{+}\to 0_{g.s.}^{+})$ values and it describes well the experimental pattern for ${}^{104-114}$Sn; the $B(E2;4_1^{+}\to 2_1^{+})$ values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in ${}^{108}$Sn. This result provides insight in the hitherto unexplained $B(E2;4_1^{+}\to 2_1^{+})/B(E2;2_1^{+}\to 0_{g.s.}^{+})<1$ anomaly.

arXiv commentV1: 6 pages, 3 figures, 1 table, theoretical interpretation described in detail in the arXiv paper of A.P.Zuker (cross-reference) V2: added reference to A.P. Zuker paper (arXiv:1905.11479)

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Cited by in corpus (6)

• Electromagnetic Properties of Indium Isotopes Elucidate the Doubly Magic Character of ${}^{100}$Sn
• Quadrupole dominance in the light Sn and in the Cd isotopes
• Lifetime Measurements in the Even-Even ${}^{102-108}$Cd Isotopes
• Fast trajectory reconstruction techniques for the large acceptance magnetic spectrometer VAMOS++
• Quadrupole dominance in light Cd and Sn isotopes
• Relation between E2 transitions in even--even and odd-mass nuclei