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

2019/05/29 by M. Siciliano, J. J. Valiente-Dobón, A. Goasduff +67 · 1 citation
Physics and Astronomy · #nucl-ex

paper · pdf · doi:10.1016/j.physletb.2020.135474

V1: 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)

arxiv created 2019/05/29 · arxiv updated 2020/05/13

Abstract

The lifetimes of the low-lying excited states 2⁺ and 4⁺ have been directly measured in the neutron-deficient ^106,108Sn isotopes. The nuclei were populated via a deep-inelastic reaction and the lifetime measurement was performed employing a differential plunger device. The emitted γ 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; 2₁⁺ → 0_g.s.⁺) values and it describes well the experimental pattern for ^104-114Sn; the B(E2; 4₁⁺ → 2₁⁺) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in ¹⁰⁸Sn. This result provides insight in the hitherto unexplained B(E2; 4₁⁺ → 2₁⁺)/B(E2; 2₁⁺ → 0_g.s.⁺) < 1 anomaly.

Citations

• Quadrupole dominance in light Cd and Sn isotopes

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• Charge Radii Measurements of Exotic Tin Isotopes in the Proximity of N=50 and N=82