The T=0 neutron-proton pairing correlations in the superdeformed rotational bands around 60Zn

The superdeformed bands in 58Cu, 59Cu, 60Zn, and 61Zn are analyzed within the frameworks of the Skyrme-Hartree-Fock as well as Strutinsky-Woods-Saxon total routhian surface methods with and without the T=1 pairing correlations. It is shown that a consistent description within these standard approaches cannot be achieved. A T=0 neutron-proton pairing configuration mixing of signature-separated bands in 60Zn is suggested as a possible solution to the problem.Comment: 9 ReVTex pages, 10 figures, submitted to Phys. Rev.

Isovector and isoscalar superfluid phases in rotating nuclei

The subtle interplay between the two nuclear superfluids, isovector T=1 and isoscalar T=0 phases, are investigated in an exactly soluble model. It is shown that T=1 and T=0 pair-modes decouple in the exact calculations with the T=1 pair-energy being independent of the T=0 pair-strength and vice-versa. In the rotating-field, the isoscalar correlations remain constant in contrast to the well known quenching of isovector pairing. An increase of the isoscalar (J=1, T=0) pair-field results in a delay of the bandcrossing frequency. This behaviour is shown to be present only near the N=Z line and its experimental confirmation would imply a strong signature for isoscalar pairing collectivity. The solutions of the exact model are also discussed in the Hartree-Fock-Bogoliubov approximation.Comment: 5 pages, 4 figures, submitted to PR

Angular momentum projection of cranked Hartree-Fock states: Application to terminating bands in A~44 nuclei

We present the first systematic calculations based on the angular-momentum projection of cranked Slater determinants. We propose the Iy --> I scheme, by which one projects the angular momentum I from the 1D cranked state constrained to the average spin projection of =I. Calculations performed for the rotational band in 46Ti show that the AMP Iy --> I scheme offers a natural mechanism for correcting the cranking moment of inertia at low-spins and shifting the terminating state up by ~2 MeV, in accordance with data. We also apply this scheme to high-spin states near the band termination in A~44 nuclei, and compare results thereof with experimental data, shell-model calculations, and results of the approximate analytical symmetry-restoration method proposed previously.Comment: 9 RevTeX pages, 8 EPS figures, submitted to Physical Review

Microscopic calculations of isospin mixing in N~Z nuclei and isospin-symmetry-breaking corrections to the superallowed beta-decay

Recently, we have applied for the first time the angular momentum and isospin projected nuclear density functional theory to calculate the isospin-symmetry breaking (ISB) corrections to the superallowed beta-decay. With the calculated set of the ISB corrections we found |V_{ud}|=0.97447(23) for the leading element of the Cabibbo-Kobayashi-Maskawa matrix. This is in nice agreement with both the recent result of Towner and Hardy [Phys. Rev. {\bf C77}, 025501 (2008)] and the central value deduced from the neutron decay. In this work we extend our calculations of the ISB corrections covering all superallowed transitions A,I^\pi=0^+,T=1,T_z \rightarrow A,I^\pi=0^+,T=1,T_z+1 with T_z =-1,0 and A ranging from 10 to 74.Comment: Invited talk presented by WS at the Nordic Conference on Nuclear Physics, June 13-17, 2011, Stockholm, Sweden; Accepted for publication in Physica Scripta, Figure 1 has been correcte

Hyperfine interactions of 57Fe in Pt3Fe in Pt 3Fe - Ab initio and Mossbauer effect studies

The Mossbauer effect and ab initio investigations of an electric ¯eld gradient at 57Fe nuclei in Pt3Fe compound are presented. It is shown that nonzero 57Fe electric ¯eld gradient exists in the cubic Pt3Fe. Ab initio study of Pt3Fe in antiferromagnetic state con¯rms the presence of electric ¯eld gradient at 57Fe nuclei. Lattice, local valence electron (3d, 4p) and weakly bound 3p core electron contributions to electric ¯eld gradient are separated out and discussed in the context of the electronic structure changes upon the antiferromagnetic phase transition

Cranked Relativistic Hartree-Bogoliubov Theory: Superdeformed Bands in the A∼190A\sim 190 Region

Cranked Relativistic Hartree-Bogoliubov (CRHB) theory is presented as an extension of Relativistic Mean Field theory with pairing correlations to the rotating frame. Pairing correlations are taken into account by a finite range two-body force of Gogny type and approximate particle number projection is performed by Lipkin-Nogami method. This theory is applied to the description of yrast superdeformed rotational bands observed in even-even nuclei of the $A\sim 190$ mass region. Using the well established parameter sets NL1 for the Lagrangian and D1S for the pairing force one obtains a very successful description of data such as kinematic ($J^{(1)}$) and dynamic ($J^{(2)}$) moments of inertia without any adjustment of new parameters. Within the present experimental accuracy the calculated transition quadrupole moments $Q_t$ agree reasonably well with the observed data.Comment: 6 pages including 4 PostScript figures, uses RevTex, revised version, Phys.Rev. C, Rapid Communications, in pres

Pronounced Shape Change Induced by Quasiparticle Alignment

Mean lifetimes of high-spin states of 74Kr have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the 40Ca(40Ca,α2p) reaction at a beam energy of 160 MeV with the GASP γ-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations

Local Density Approximation for proton-neutron pairing correlations. I. Formalism

In the present study we generalize the self-consistent Hartree-Fock-Bogoliubov (HFB) theory formulated in the coordinate space to the case which incorporates an arbitrary mixing between protons and neutrons in the particle-hole (p-h) and particle-particle (p-p or pairing) channels. We define the HFB density matrices, discuss their spin-isospin structure, and construct the most general energy density functional that is quadratic in local densities. The consequences of the local gauge invariance are discussed and the particular case of the Skyrme energy density functional is studied. By varying the total energy with respect to the density matrices the self-consistent one-body HFB Hamiltonian is obtained and the structure of the resulting mean fields is shown. The consequences of the time-reversal symmetry, charge invariance, and proton-neutron symmetry are summarized. The complete list of expressions required to calculate total energy is presented.Comment: 22 RevTeX page

Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism

The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital and total angular momenta along the rotational axis effectively creating additional angular momentum. This effect leads to the increase of kinematic and dynamic moments of inertia at given rotational frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review