arXiv subjects

Víctor Velázquez-Aguilar

Publications and source records attributed to Víctor Velázquez-Aguilar.

2 recordsLinked to original sources

arXiv2026

Microscopic study of low-lying energy levels and electromagnetic properties in even-even $^{168-178}$Yb nuclei

Employing methods based on symmetries for the theoretical description of rare-earth nuclei offers many advantages. Among these, the pseudo-SU(3) shell model has proved to be a very useful method to describe characteristics of these systems and to understand various properties. A theoretical description of the low-lying energy spectrum and electromagnetic properties of isotopes $^{168-178}$Yb is carried out for the first time with this model, comparing theoretical results with the experimental values, where possible. The Hamiltonian includes the $Q \cdot Q$ term which preserves the symmetry, as well as the breaking symmetry of Nilsson and pairing terms. Additionally, three rotor type terms are included that allow us to make a subtle adjustment of the spectrum. The results show that the energy spectrum, the B(E2) transitions, the g-factors and the electric quadrupole moments can be described adequately with the model. Although the model is a powerful tool in the description of low-lying properties of normal parity in heavy deformed nuclei, it finds its strongest limitation in the abnormal parity sector, which has been left out of the description.

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arXiv2026

Theoretical study of normal deformed rotational bands of odd-mass $^{167,169,171}$Lu nuclei

The theoretical description of nuclear structure in rare earth nuclei represents a significant challenge for many shell models. This difficulty stems from the size of the configuration space involved. Methods based on symmetries provide significant advantages. Furthermore, the pseudo-SU(3) shell model has proven to be very useful in the description of these systems. In particular, we propose to study the energy spectra of the rotational bands with normal deformation at low and medium spin ($J\leq35/2$), the quadrupole moments, and the deformation parameter $γ$ associated with the states, as well as the B(E2) transition strengths in the $^{167,169,171}$Lu nuclei. The Hamiltonian includes $Q \cdot Q$, Nilsson, and pairing terms, parameterized in a systematic way, in addition to three rotor-like terms that enable fine tuning of the spectra. Our calculations predict collective rotational bands with prolate normal deformation in most cases. The exception is the $1/2^+$ band in $^{171}$Lu with a triaxial shape. The quadrupole moments vary along the bands, increasing in absolute value with spin. The $γ$ deformation parameter remains nearly constant along the bands, and the B(E2) values suggest bands with collective character and normal deformation. The agreement and limitations of the model are discussed.

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