Orateur
Description
The 48Cr nucleus stands as a paradigmatic example of a nuclear rotor within the pf-shell.
Available shell-model and mean-field calculations for this nucleus consistently
reveal features of well-deformed systems: a rotational-type energy spectrum,
a bell-shaped trend in B(E2; 2+->0+) transitions across the Cr isotopic chain (peaking at 48Cr),
and significant ground-state deformation parameters.
Despite this robust theoretical framework, the experimentally measured B(E2; 4+->2+)/B(E2; 2+->0+)
ratio—close to 1 is not consistent with the expectations for a deformed rotor (value near 1.8).
This discrepancy has motivated a new experimental proposal for Coulomb excitation of 48Cr at GANIL (E890_23).
In this work, we present a comprehensive, updated shell-model analysis of 48Cr and of neighbouring nuclei.
We provide a complete set of predictions for the energy spectra, B(E2) transition strengths,
deformation parameters, and, for the first time, of the shape invariants, and discuss their implications
in the context of existing experimental data and other theoretical approaches.