The discovery of presolar grains in primitive meteorites has initiated a new era of research in the study of stellar nucleosynthesis. However, the accurate classification of presolar grains as being ...of specific stellar origins is particularly challenging. Recently, it has been suggested that sulfur isotopic abundances may hold the key to definitively identifying presolar grains with being of nova origins and, in this regard, the astrophysical 33Cl ( p , γ ) 34Ar reaction is expected to play a decisive role. As such, we have performed a detailed γ -ray spectroscopy study of 34Ar . Excitation energies have been measured with high precision and spin-parity assignments for resonant states, located above the proton threshold in 34Ar , have been made for the first time. Uncertainties in the 33Cl (p , γ) reaction have been dramatically reduced and the results indicate that a newly identified ℓ = 0 resonance at Er = 396.9 ( 13 ) keV dominates the entire rate for T = 0.25 – 0.40 GK . Furthermore, nova hydrodynamic simulations based on the present work indicate an ejected 32S /33S abundance ratio distinctive from type-II supernovae and potentially compatible with recent measurements of a presolar grain.
The reaction of a pulsed 18O beam on a self-supporting and gold-backed isotopically-enriched 164Dy target of thickness 6.3 mg/cm2 at separate primary beam energies of 71, 76 and 80 MeV was studied at ...the accelerator at the ALTO facility of the IPN Orsay. The γ rays produced were detected using the newly-constructed ν-Ball spectrometer which comprised of HPGe and LaBr3(Ce) detectors. This conference paper describes the methodology and effectiveness of multiplicity/sum-energy gating, for channel selection between fusion evaporation events and lower multiplicity/energy events from inelastic nuclear scattering and Coulomb excitation of the target, and from two-neutron transfer reactions to 166Dy.
Low-lying states in the isotope Xe130 were populated in a Coulomb-excitation experiment performed at CERN's HIE-ISOLDE facility. The magnitudes and relative signs of seven E2 matrix elements and one ...M1 matrix element coupling five low-lying states in Xe130 were determined using the semiclassical coupled-channel Coulomb-excitation least-squares search code gosia. The diagonal E2 matrix elements of both the 21+ and 41+ states were extracted for the first time. The reduced transition strengths are in line with those obtained from previous measurements. Experimental results were compared with the general Bohr Hamiltonian with the microscopic input from mean-field theory utilizing universal nuclear energy density functional (UNEDF0), shell-model calculations using the GCN50:82 and SN100PN interactions, and simple phenomenological models (Davydov-Filippov and γ-soft). The extracted shape parameters indicate triaxial-prolate deformation in the ground-state band. In general, good agreement between theoretical predictions and experimental values was found, while neither phenomenological model was found to provide an adequate description of Xe130.
The low-lying nuclear structure of even-even Zn isotopes ranging from
62
Zn to
70
Zn has been comprehensively examined through large scale shell model calculations. These calculations encompassed the ...f
5
/
2
p
3
/
2
,
1
/
2
g
9
/
2
(fpg) model space without any truncation, employing
56
Ni as an inert core. Two different effective interactions, JUN45 and jj44b, were utilized in these calculations. Various critical observables, including excitation energies, reduced transition strengths, and electric quadrupole moments, were computed and then evaluated in the context of existing experimental data. The configurations of the resulting wave functions were also thoroughly analyzed. Furthermore, occupation probabilities for distinct single-particle orbitals were determined, with particular attention given to the pivotal role of the g
9
/
2
orbital in elucidating the nuclear structure of heavy Zn isotopes. Additionally, rotational invariants were calculated for the ground state, shedding light on a prolate deformation in
62
Zn and
64
Zn, while suggesting moderate prolate-triaxial excitations in
66
Zn,
68
Zn, and
70
Zn. These findings hold significant relevance for interpreting the intriguing outcomes of sub-barrier Coulomb excitation experiments, offering invaluable insights into the static electromagnetic properties of the nucleus through a model-independent approach.
Octupole correlations near Te 110 Testov, D. A.; Bakes, S.; Valiente-Dobón, J. J. ...
Physical review. C,
04/2021, Letnik:
103, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The lifetime of the 2+ and 9-, 11-, 13-, 15- states in the neutron-deficient Te110 was measured for the first time using the recoil distance Doppler shift technique. The reported value of the reduced ...transition probability B(E2;0g.s+→2+)=4.3(8)×103e2fm4 supports the systematic for even-mass Te isotopes and was interpreted in the framework of the large-scale shell model and cranked shell model calculations. The measured reduced transition probabilities in the negative-parity yrast band revealed the upward trend towards the high spins. The enhanced collectivity is discussed in terms of the tilted axis cranking approach and the symmetry configuration mixing method with the Gogny D1S interaction.
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