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AGATA Collaboration(Avigo, R. et al), Domingo-Pardo, C., Gadea, A., & Gonzalez, V. (2020). Low-lying electric dipole gamma-continuum for the unstable Fe-62(,)64 nuclei: Strength evolution with neutron number. Phys. Lett. B, 811, 135951–6pp.
Abstract: The gamma-ray emission from the nuclei Fe-62,Fe-64 following Coulomb excitation at bombarding energy of 400-440 AMeV was measured with special focus on E1 transitions in the energy region 4-8 MeV. The unstable neutron-rich nuclei Fe-62,Fe-64 were produced at the FAIR-GSI laboratories and selected with the FRS spectrometer. The gamma decay was detected with AGATA. From the measured gamma-ray spectra the summed E1 strength is extracted and compared to microscopic quasi-particle phonon model calculations. The trend of the E1 strength with increasing neutron number is found to be fairly well reproduced with calculations that assume a rather complex structure of the 1(-) states (three-phonon states) inducing a strong fragmentation of the E1 nuclear response below the neutron binding energy.
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AGATA Collaboration(Siciliano, M. et al), Gadea, A., Perez-Vidal, R. M., & Domingo-Pardo, C. (2020). Pairing-quadrupole interplay in the neutron-deficient tin nuclei: First lifetime measurements of low-lying states in Sn-106,Sn-108. Phys. Lett. B, 806, 135474–7pp.
Abstract: The lifetimes of the low-lying excited states 2(+) and 4(+) have been directly measured in the neutron-deficient Sn-106,Sn-108 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)(+) -> 0(g.s)(+)) values and it describes well the experimental pattern for Sn104-114 ; the B(E2;(+)(4) -> 2(1)(+)) values, measured here for the first time, depend critically on a delicate pairing-quadrupole balance, disclosed by the very precise results in Sn-108.
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Bartram, G. et al, Morales, A. I., Orrigo, S. E. A., Rodriguez-Garcia, D., & Tain, J. L. (2026). Structure of the semi-magic 203Ir and 202Os nuclei. Phys. Lett. B, 880, 140790–5pp.
Abstract: The internal structures of the semi-magic, neutron-rich N=126 nuclei, 203Ir and 202Os, were studied. The nuclei of interest were produced using relativistic-energy projectile fragmentation of a 208Pb beam at the GSI facility in Germany. Internal isomeric decays were investigated via delayed gamma-ray spectroscopy. In 203Ir, four observed transitions were associated with parallel decay branches from an isomeric yrast 19/2+ state. An observed weak delayed gamma ray in 202Os is discussed in connection with a predicted isomeric 10+ state. Spin and parity assignments were made by comparison of the experimental data with state-of-the-art shell model calculations using three different shell-model parametrisations. It was found that the two-body interaction implemented to reproduce isomeric decays of the less exotic 204Pt and 206Hg isotones was the only interaction that describes the present experimental data. The persistence of the isomeric states, and the reproduction of the structure of the most neutron-rich N=126 nuclei ever observed, indicates that the N=126 shell closure remains robust.
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Cho, Y. et al, & Perez-Vidal, R. M. (2026). Regularity of core coupled high-spin structure in neutron-rich 196-202Au isotopes approaching N=126. Phys. Lett. B, 878, 140558–7pp.
Abstract: Excited states built upon long-lived high-spin isomers in hard-to-reach neutron-rich Au (Z = 79) isotopes were populated using multi-nucleon transfer reactions between 136Xe and 198Pt at 7 MeV/u. These states in 196,198-202Au were identified for the first time using the powerful combination of the VAMOS++ spectrometer, the CATLIFE detection system, and the AGATA 1-ray tracking array. Their measured energies exhibit remarkable regularity as a function of neutron number and are seen to be inherited from the energies of yrast-band members in the corresponding Hg (Z = 80) isotope. Large-scale shell-model calculations reproduce the observed regularity and show that these states arise from the unique-parity orbitals 20h11/2 and v0i13/2 coupled to the Hg core. This regularity is due to the dominant proton configurations of the Hg and Au isotopes, where the level energies are almost independent of different neutron-orbital occupancies. The calculated Au wave functions show significant higher-spin components of the corresponding Hg core, unlike what is expected in the conventional interpretation in terms of the weak-coupling/decoupling limits of the particle-core coupling model.
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Davesne, D., Meyer, J., Pastore, A., & Navarro, J. (2015). Partial wave decomposition of the N3LO equation of state. Phys. Scr., 90(11), 114002–6pp.
Abstract: By means of a partial wave decomposition, we separate their contributions to the equation of state (EoS) of symmetric nuclear matter for the N3LO pseudo-potential. In particular, we show that although both the tensor and the spin-orbit terms do not contribute to the EoS, they give a non-vanishing contribution to the separate (JLS) channels.
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