Two fits of the pairing residual interaction in the rare-earth region are independently performed. One is made on the odd-even staggering of masses by comparing measured and explicitly calculated three-point binding-energy differences centered on odd-even nuclei. Another deals with the moments of inertia of the first 2 + states of well deformed even-even nuclei upon comparing experimental data with the results of Inglis-Belyaev moments (supplemented by a crude estimate of the so-called Thouless-Valatin corrections). The sample includes 24 even-even and 31 odd-mass nuclei selected according to two criteria: they should have good rotor properties and should not correspond to low pairing-correlation regimes in their ground states. Calculations are performed in the self-consistent Hartree-Fock plus BCS framework (implementing a self-consistent blocking in the case of oddmass nuclei). The Skyrme SIII parametrization is used in the particle-hole channel and the fitted quantities are the strengths of |Tz| = 1 proton and neutron seniority residual interactions. As a result the two fits yield sets of strengths in excellent agreement: about 0.1% for the neutron parameters and 0.2% for protons. In contrast when one performs such a fit on odd-even staggering from quantities deduced from BCS gaps or minimal quasiparticle energies in even-even nuclei, as is traditional, one obtains results significantly different from those obtained in the same nuclei by a fit of moments of inertia. As a conclusion, beyond providing a phenomenological tool for microscopic calculations in this region, we have illustrated the proposition made in the seminal paper of Bohr, Mottelson and Pines that moments of inertia and odd-even staggering in selected nuclei were excellent measuring sticks of nuclear pairing correlations. Furthermore we have assessed the validity of our theoretical approach which includes simple yet apparently reasonable assumptions (seniority residual interaction, parametrization of its matrix elements as functions of the nucleon numbers and global Thouless-Valatin renormalisation of Inglis-Belyaev moments of inertia).

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Description of static nuclear properties is one of the main aims of theoretical nuclear physics studies. This work presents the uncertainties due to pairing fit procedure for three static nuclear quantities of rare-earth nuclei, namely the nuclear charge radius, electric quadrupole moment, and the moment of inertia. The Hartree-Fock (HF)-plus-pairing approach was employed with pairing correlations treated within the Bardeen-Cooper-Schrieffer (BCS) framework. The Skyrme SIII parametrization were chosen to approximate the effective nucleon-nucleon interaction while seniority force is used for the pairing interaction. In this work, two sets of pairing strengths obtained from different fit procedures were chosen. Calculated result shows that the moment of inertia is hugely dependent on variation of pairing strengths.

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