Disentangling the nuclear shape coexistence in even-even Hg isotopes using the interacting boson model

We intend to provide a consistent description of the even-even Hg isotopes, 172-200Hg, using the interacting boson model including configuration mixing. We pay special attention to the description of the shape of the nuclei and to its connection with the shape coexistence phenomenon.Comment: To appear in CGS15 conference proceedings (EPJ Web of Conferences

The influence of intruder states in even-even Po isotopes

We study the role of intruder states and shape coexistence in the even-even $^{190-206}$Po isotopes, through an interacting boson model with configuration mixing calculation. We analyzed the results in the light of known systematics on various observable in the Pb region, paying special attention to the unperturbed energy systematics and quadrupole deformation. We find that shape coexistence in the Po isotopes behaves in very much the same way as in the Pt isotopes, i.e., it is somehow hidden, contrary to the situation in the Pb and the Hg isotopes.Comment: Contribution to the Nuclear Structure and Dynamics 2015 (Portorose, Slovenia) proceeding

Nuclear shape coexistence in Po isotopes: An interacting boson model study

Background: The lead region, Po, Pb, Hg, and Pt, shows up the presence of coexisting structures having different deformation and corresponding to different particle-hole configurations in the Shell Model language. Purpose: We intend to study the importance of configuration mixing in the understanding of the nuclear structure of even-even Po isotopes, where the shape coexistence phenomena are not clear enough. Method: We study in detail a long chain of polonium isotopes, 190-208Po, using the interacting boson model with configuration mixing (IBM-CM). We fix the parameters of the Hamiltonians through a least-squares fit to the known energies and absolute B(E2) transition rates of states up to 3 MeV. Results: We obtained the IBM-CM Hamiltonians and we calculate excitation energies, B(E2)'s, electric quadrupole moments, nuclear radii and isotopic shifts, quadrupole shape invariants, wave functions, and deformations. Conclusions: We obtain a good agreement with the experimental data for all the studied observables and we conclude that shape coexistence phenomenon is hidden in Po isotopes, very much as in the case of the Pt isotopes.Comment: To be published in Physical Review C. arXiv admin note: text overlap with arXiv:1312.459

Identifying neutrinos and antineutrinos in neutral-current scattering reactions

We study neutrino-induced nucleon knockout from nuclei. Expressions for the induced polarization are derived within the framework of the independent-nucleon model and the non-relativistic plane-wave approximation. Large dissimilarities in the nucleon polarization asymmetries are observed between neutrino- and antineutrino-induced processes. These asymmetries represent a potential way to distinguish between neutrinos and antineutrinos in neutral-current neutrino-scattering on nuclei. We discuss astrophysical applications of these polarization asymmetries. Our findings are illustrated for neutrino scattering on $^{16}$O and $^{208}$Pb.Comment: 5 pages, 5 figures, accepted for publication in Phys. Rev. Let

Livonia under the Polish-Lithuanian Commonwealth. The struggle for power and the social transformation

Translated by PhD Andreas Keller. The article was submitted on 18.04.2014.The article describes the controversial correlation of forces in Livonia’s fight to retain its status quo. The geopolitical situation caused Livonia, though a sovereign but highly dependent state, to gradually disappear. Livonia’s structure was far from monolithic; it was a complex of secular, church, order and city jurisdictions. There were estates that had either lost or acquired rights. Internationally, this European province, whose territory was being claimed by the Polish-Lithuanian Commonwealth, Sweden, Denmark, and Russia, was incapable of surviving in the intensifying political and military confrontations that dominated the region in the last third of the 17th century.Дается развернутая панорама противоречивого соотношения сил в борьбе Ливонии за сохранение своего status quo. Стремительно менявшаяся геополитическая ситуация сложилась не в пользу существования Ливонии как сильно зависимого, но все же самостоятельного государственного образования, что привело к его постепенному упразднению. Внутреннее устройство Ливонии не было монолитным, это был сложный конгломерат различных юрисдикций: светской, церковной, орденской, городской. Здесь тоже были сословия, потерявшие или приобретшие свои права. Во внешнеполитической перспективе европейская провинция, на которую заявляли свои права польско-литовское государство, Швеция, Дания и Россия не могла устоять в обострившейся обстановке военно-политического противостояния сил, доминировавших в регионе, и к концу XVI в. это стало очевидным фактом

Shape evolution and shape coexistence in Pt isotopes: comparing interacting boson model configuration mixing and Gogny mean-field energy surfaces

The evolution of the total energy surface and the nuclear shape in the isotopic chain $^{172-194}$Pt are studied in the framework of the interacting boson model, including configuration mixing. The results are compared with a self-consistent Hartree-Fock-Bogoliubov calculation using the Gogny-D1S interaction and a good agreement between both approaches shows up. The evolution of the deformation parameters points towards the presence of two different coexisting configurations in the region 176 $\leq$ A $\leq$ 186.Comment: Submitted to PR

Spin-dependent neutrino-induced nucleon knockout

We study neutrino-induced nucleon knockout off atomic nuclei and examine the polarization properties of the ejectile. A detailed study of the spin dependence of the outgoing nucleon is presented. The numerical results are derived within a non-relativistic plane-wave impulse-approximation approach. Our calculations reveal large polarization asymmetries, and clear dissimilarities between neutrino- and antineutrino-induced reactions. They reflect the fact that neutrino-induced nucleon knockout is dominated by the transverse axial current and gains its major contributions from forward nucleon emission and backward lepton scattering.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.

Shell-model description of monopole shift in neutron-rich Cu

Variations in the nuclear mean-field, in neutron-rich nuclei, are investigated within the framework of the nuclear shell model. The change is identified to originate mainly from the monopole part of the effective two-body proton-neutron interaction. Applications for the low-lying states in odd-$A$ Cu nuclei are presented. We compare the results using both schematic and realistic forces. We also compare the monopole shifts with the results obtained from large-scale shell-model calculations, using the same realistic interaction, in order to study two-body correlations beyond the proton mean-field variations.Comment: Phys. Rev. C (in press

A theoretical description of energy spectra and two-neutron separation energies for neutron-rich zirconium isotopes

Very recently the atomic masses of neutron-rich Zr isotopes, from $^{96}$Zr to $^{104}$Zr, have been measured with high precision. Using a schematic Interacting Boson Model (IBM) Hamiltonian, the evolution from spherical to deformed shapes along the chain of Zr isotopes, describing at the same time the excitation energies as well as the two-neutron separation energies, can be rather well reproduced. The interplay between phase transitions and configuration mixing of intruder excitations in this mass region is succinctly addressed.Comment: Accepted in European Journal of Physics

Nuclear binding energies: Global collective structure and local shell-model correlations

Nuclear binding energies and two-neutron separation energies are analyzed starting from the liquid-drop model and the nuclear shell model in order to describe the global trends of the above observables. We subsequently concentrate on the Interacting Boson Model (IBM) and discuss a new method in order to provide a consistent description of both, ground-state and excited-state properties. We address the artefacts that appear when crossing mid-shell using the IBM formulation and perform detailed numerical calculations for nuclei situated in the 50-82 shell. We also concentrate on local deviations from the above global trends in binding energy and two-neutron separation energies that appear in the neutron-deficient Pb region. We address possible effects on the binding energy, caused by mixing of low-lying $0^{+}$ intruder states into the ground state, using configuration mixing in the IBM framework. We also study ground-state properties using a deformed mean-field approach. Detailed comparisons with recent experimental data in the Pb region are amply discussed.Comment: 69 pages, TeX (ReVTeX). 23 eps figures. 1 table. Modified version. Accepted in Nucl. Phys.