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Nuclear Theory·nucl-th

Wednesday·August 5, 2015

9 papers—3 primary·6 cross-listed

All9Primary3Cross-lists6
  1. 01

    [Submitted on 4 Aug 2015]

    Identification of Highly Deformed Even-Even Nuclides in the Neutron- and Proton-Rich Regions of the Nuclear Chart from the B(E2) and E2 Predictions in the Generalized Differential Equation Model

    R. C. Nayak · S. Pattnaik

    We identify here possible occurrence of large deformations in the neutron- and proton-rich regions of the nuclear chart from extensive predictions of the values of the reduced quadrupole transition probability B-E2 for the transition from the ground state to the first 2+ state and the corresponding excitation energy E2 of even-even nuclei in the recently developed Generalized Differential Equation model exclusively meant for these physical quantities. This is made possible from our analysis of the predicted values of these two physical quantities and the corresponding deformation parameters derived from them such as the quadrupole deformation beta-2, the ratio of beta-2 to the Weisskopf single-particle beta-2 and the intrinsic electric quadruplole moment , calculated for a large number of both known as well as hitherto unknown even-even isotopes of Oxygen to Fermium (Z=8 to 100). Our critical analysis of the resulting data convincingly support possible existence of large collectivity for the nuclides 30,32 Ne, 34 Mg, 60 Ti, 42,62,64 Cr, 50,68 Fe, 52,72 Ni, 72,70,96 Kr, 74,76 Sr,78,80,106,108 Zr , 82,84,110,112 Mo, 140 Te,144 Xe, 148 Ba, 122 Ce, 128,156 Nd, 130,132,158,160 Sm and 138,162,164,166 Gd, whose values of beta-2 are found to exceed 0.3 and even 0.4 in some cases. Our findings of large deformations in the exotic neutron-rich regions support the existence of another Island of Inversion in the heavy-mass region possibly caused by breaking of the N=70 sub-shell closure.

    Comments:
    15 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.00660 [pdf]
    IJMPE(2015)·2 citations
  2. 02

    [Submitted on 4 Aug 2015]

    Sextic potential for -rigid prolate nuclei

    P. Buganu · R. Budaca

    The equation of the Bohr-Mottelson Hamiltonian with a sextic oscillator potential is solved for -rigid prolate nuclei. The associated shape phase space is reduced to three variables which are exactly separated. The angular equation has the spherical harmonic functions as solutions, while the equation is brought to the quasi-exactly solvable case of the sextic oscillator potential with a centrifugal barrier. The energies and the corresponding wave functions are given in closed form and depend, up to a scaling factor, on a single parameter. The and states are exactly determined, having an important role in the assignment of some ambiguous states for the experimental bands. Due to the special properties of the sextic potential, the model can simulate, by varying the free parameter, a shape phase transition from a harmonic to an anharmonic prolate -soft rotor crossing through a critical point. Numerical applications are performed for 39 nuclei: Ru, Mo, Xe, Ce, Nd, Sm, Gd, Dy, Os, Pt, Hg and Ra. The best candidates for the critical point are found to be Ru and Xe, followed closely by Xe, Os, Pt and Nd.

    Comments:
    21 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1508.00728 [pdf]
    J.Phys.G(2015)·57 citations
  3. 03

    [Submitted on 4 Aug 2015]

    General classical and quantum-mechanical description of magnetic resonance: An application to electric-dipole-moment experiments

    Alexander J. Silenko🇧🇾

    A general theoretical description of a magnetic resonance is presented. This description is necessary for a detailed analysis of spin dynamics in electric-dipole-moment experiments in storage rings. General formulas describing a behavior of all components of the polarization vector at the magnetic resonance are obtained for an arbitrary initial polarization. These formulas are exact on condition that the nonresonance rotating field is neglected. The spin dynamics is also calculated at frequencies far from resonance with allowance for both rotating fields. A general quantum-mechanical analysis of the spin evolution at the magnetic resonance is fulfilled and the full agreement between the classical and quantum-mechanical approaches is shown. Quasimagnetic resonances for particles and nuclei moving in noncontinuous perturbing fields of accelerators and storage rings are considered. Distinguishing features of quasimagnetic resonances in storage ring electric-dipole-moment experiments are investigated in detail. The exact formulas for the effect caused by the electric dipole moment are derived. The difference between the resonance effects conditioned by the rf electric-field flipper and the rf Wien filter is found and is calculated for the first time. The existence of this difference is crucial for the establishment of a consent between analytical derivations and computer simulations and for checking spin tracking programs. Main systematical errors are considered.

    Comments:
    29 pages
    Subjects:
    Nuclear Theory (nucl-th); cond-mat.other (cond-mat.other); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th)
    arXiv:
    1508.00742 [pdf]
    EPJC(2017)·13 citations

Affiliations

first authorsco-authorsvia INSPIRE