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Nuclear Theory·nucl-th

Thursday·March 3, 2022

8 papers—3 primary·5 cross-listed

All8Primary3Cross-lists5
  1. 01

    Analysis of Peierls-Yoccoz rotational energy of nuclei with semi-realistic interaction

    K. Abe · H. Nakada

    The Peierls-Yoccoz (PY) rotational energy of nuclei has been analyzed by the angular-momentum projection (AMP) on the axial Hartree-Fock solutions, by using the semi-realistic effective Hamiltonian M3Y-P6. The rotational energy is decomposed into contributions of the individual terms of the Hamiltonian, and their ratios to the total PY rotational energy are calculated. Except for light or weakly-deformed nuclei, the ratios of the individual terms of the Hamiltonian are insensitive to nuclides and deformation. The contributions of kinetic energies are large and close to the rigid-rotor values, although those of central forces are sizable. For light or weakly-deformed nuclei, the ratios significantly depend on nuclei and deformation. The contributions of noncentral forces are not negligible. Regardless of nuclides, the attractive forces decrease the moment-of-inertia, and the repulsive forces increase it. A general formula for the PY rotational energy is derived, which suggests that higher-order terms of the cumulant expansion play roles in the rotational energy and the moment-of-inertia for light or weakly-deformed nuclei.

    nucl-thPRC(2022)·3 citations
  2. 02

    Shell-model calculation of Mo double- decay

    L. Coraggio🇮🇹 · N. Itaco🇮🇹 · G. De Gregorio🇮🇹 · A. Gargano🇮🇹 · R. Mancino🇮🇹 · F. Nowacki🇫🇷

    For the first time, the calculation of the nuclear matrix element of the double- decay of Mo, with and without the emission of two neutrinos, is performed in the framework of the nuclear shell model. This task is accomplished starting from a realistic nucleon-nucleon potential, then the effective shell-model Hamiltonian and decay operators are derived within the many-body perturbation theory. The exotic features which characterize the structure of Mo isotopes -- such as shape coexistence and triaxiality softness -- push the shell-model computational problem beyond its present limits, making it necessary to truncate the model space. This has been done with the goal to preserve as much as possible the role of the rejected degrees of freedom in an effective approach that has been introduced and tested in previous studies. This procedure is grounded on the analysis of the effective single-particle energies of a large-scale shell-model Hamiltonian, that leads to a truncation of the number of the orbitals belonging to the model space. Then, the original Hamiltonian generates a new one by way of a unitary transformation onto the reduced model space, to retain effectively the role of the excluded single-particle orbitals. The predictivity of our calculation of the nuclear matrix element for the neutrinoless double- decay of Mo is supported by the comparison with experiment of the calculated spectra, electromagnetic transition strengths, Gamow-Teller transition strengths and the two-neutrino double-beta nuclear matrix elements.

    nucl-thhep-exhep-phnucl-exPRC(2022)·54 citations
  3. 03

    Nuclear Structure with Discrete Non-Orthogonal Shell-Model : new frontiers

    D. D. Dao🇫🇷 · Frédéric Nowacki🇫🇷

    We present developments and applications for the diagonalization of shell-model hamiltonians in a discrete non-orthogonal basis (DNO-SM). The method, and its actual numerical implementation CARINA, based on mean-field and beyond-mean field techniques has already been applied in previous studies and is focused on basis states selection optimization. The method is benchmarked against a full set of shell exact diagonalizations, and is applied for the first time to the heavy deformed No nucleus.

    nucl-thnucl-exPRC(2022)·50 citations

Affiliations

first authorsco-authorsvia INSPIRE