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N. A. Smirnova

Publications and source records attributed to N. A. Smirnova.

24 records · Page 2Linked to original sources
arXiv2003

On the asymmetry of Gamow-Teller beta-decay rates in mirror nuclei in relation with second-class currents

The theoretical evaluation of major nuclear structure effects on the asymmetry of allowed Gamow-Teller beta-decay rates in light mirror nuclei is presented. The calculations are performed within the shell model, using empirical isospin-nonconserving interaction and realistic Woods-Saxon radial wave functions. The revised treatment of p-shell nuclei is supplemented by systematic calculations for sd-shell nuclei and compared to experimental asymmetries when available. The results are important in connection with the possible existence of second-class currents in the weak interaction.

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arXiv2003

Geometry of random interactions

It is argued that spectral features of quantal systems with random interactions can be given a geometric interpretation. This conjecture is investigated in the context of two simple models: a system of randomly interacting d bosons and one of randomly interacting fermions in a j=7/2 shell. In both examples the probability for a given state to become the ground state is shown to be related to a geometric property of a polygon or polyhedron which is entirely determined by particle number, shell size, and symmetry character of the states. Extensions to more general situations are discussed.

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arXiv2002

Extended M1 sum rule for excited symmetric and mixed-symmetry states in nuclei

A generalized M1 sum rule for orbital magnetic dipole strength from excited symmetric states to mixed-symmetry states is considered within the proton-neutron interacting boson model of even-even nuclei. Analytic expressions for the dominant terms in the B(M1) transition rates from the first and second $2^+$ states are derived in the U(5) and SO(6) dynamic symmetry limits of the model, and the applicability of a sum rule approach is examined at and in-between these limits. Lastly, the sum rule is applied to the new data on mixed-symmetry states of 94Mo and a quadrupole d-boson ratio $nd(0^+_1)/nd(2^+_2) \approx 0.6$ is obtained in a largely parameter-independent way

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arXiv1999

IBM: parameter symmetry, hidden symmetries and transformations of boson operators

A symmetry of the parameter space of interacting boson models IBM-1 and IBM-2 is studied. The symmetry is associated with linear canonical transformations of boson operators, or, equivalently, with the existence of different realizations of the symmetry algebras of the models. The relevance of the parameter symmetry to physical observables is discussed.

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arXiv1998

Parameter Symmetry of the Interacting Boson Model

We discuss the symmetry of the parameter space of the interacting boson model (IBM). It is shown that for any set of the IBM Hamiltonian parameters (with the only exception of the U(5) dynamical symmetry limit) one can always find another set that generates the equivalent spectrum. We discuss the origin of the symmetry and its relevance for physical applications.

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