Charge radii, moments, and masses of mercury isotopes across the $N=126$ shell closure

Combining laser spectroscopy in a Versatile Arc Discharge and Laser Ion Source (VADLIS) with Penning-trap mass spectrometry at the CERN-ISOLDE facility, this work reports on mean-square charge radii of neutron-rich mercury isotopes across the <math><mrow><mi>N</mi><mo>=</mo><mn>126</mn></mrow></math> shell closure, the electromagnetic moments of <math><mmultiscripts><mi>Hg</mi><mprescripts/><none/><mn>207</mn></mmultiscripts></math>, and more precise mass values of <math><mmultiscripts><mi>Hg</mi><mprescripts/><none/><mrow><mn>206</mn><mtext>–</mtext><mn>208</mn></mrow></mmultiscripts></math>. The odd-even staggering (OES) of the mean square charge radii and the kink at <math><mrow><mi>N</mi><mo>=</mo><mn>126</mn></mrow></math> are analyzed within the framework of covariant density functional theory (CDFT), with comparisons between different functionals to investigate the dependence of the results on the underlying single-particle structure. The observed features are defined predominantly in the particle-hole channel in CDFT, since both are present in the calculations without pairing. However, the magnitude of the kink is still affected by the occupation of the <math><mrow><mi>ν</mi><mn>1</mn><msub><mi>i</mi><mrow><mn>11</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math> and <math><mrow><mi>ν</mi><mn>2</mn><msub><mi>g</mi><mrow><mn>9</mn><mo>/</mo><mn>2</mn></mrow></msub></mrow></math> orbitals with a dependence on the relative energies as well as pairing.