Electromagnetic moments of scandium isotopes and $N=28$ isotones in the distinctive $0f_{7/2}$ orbit

The electric quadrupole moment of <sup loc="post">49</sup>Sc was measured by collinear laser spectroscopy at CERN-ISOLDE to be <math altimg="si1.svg"><msub><mrow><mi>Q</mi></mrow><mrow><mi mathvariant="normal">s</mi></mrow></msub><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mo linebreak="badbreak" linebreakstyle="after">−</mo><mn>0.159</mn><mo stretchy="false">(</mo><mn>8</mn><mo stretchy="false">)</mo></math>eb, and a nearly tenfold improvement in precision was reached for the electromagnetic moments of <sup loc="post">47,49</sup>Sc. The single-particle behavior and nucleon-nucleon correlations are investigated with the electromagnetic moments of <math altimg="si2.svg"><mi>Z</mi><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>21</mn></math> isotopes and <math altimg="si3.svg"><mi>N</mi><mo linebreak="goodbreak" linebreakstyle="after">=</mo><mn>28</mn></math> isotones as valence neutrons and protons fill the distinctive <math altimg="si4.svg"><mn>0</mn><msub><mrow><mi>f</mi></mrow><mrow><mn>7</mn><mo stretchy="false">/</mo><mn>2</mn></mrow></msub></math> orbit, respectively, located between magic numbers, 20 and 28. The experimental data are interpreted with shell-model calculations using an effective interaction, and ab-initio valence-space in-medium similarity renormalization group calculations based on chiral interactions. These results highlight the sensitivity of nuclear electromagnetic moments to different types of nucleon-nucleon correlations, and establish an important benchmark for further developments of theoretical calculations.