Generalized seniority with realistic interactions in open-shell nuclei

Generalized seniority provides a truncation scheme for the nuclear shell model, based on pairing correlations, which offers the possibility of dramatically reducing the dimensionality of the nuclear shell-model problem. Systematic comparisons against results obtained in the full shell-model space are required to assess the viability of this scheme. Here, we extend recent generalized seniority calculations for semimagic nuclei, the Ca isotopes, to open-shell nuclei, with both valence protons and valence neutrons. The even-mass Ti and Cr isotopes are treated in a full major shell and with realistic interactions, in the generalized seniority scheme with one broken proton pair and one broken neutron pair. Results for level energies, orbital occupations, and electromagnetic observables are compared with those obtained in the full shell-model space. We demonstrate that, even for the Ti isotopes, significant benefit would be obtained in going beyond the approximation of one broken pair of each type, while the Cr isotopes require further broken pairs to provide even qualitative accuracy. Communicated by B M Schwenk

[1]  T. Otsuka.  Microscopic Basis of the Interacting Boson Model , 2013 .

[2]  T. Otsuka,et al.  Microscopic Calculations for O(6) Nuclei by the Interacting Boson Model , 2013 .

[3]  T. Mizusaki,et al.  Microscopic Foundations of the Interacting Boson Model from the Shell-Model Point of View , 2013 .

[4]  M. Caprio,et al.  Generalized seniority in a major shell with realistic interactions , 2012 .

[5]  Y. M. Zhao,et al.  Spherical to deformed shape transitions in the nucleon pair shell model , 2012, 1207.2297.

[6]  M. Caprio,et al.  Generalized seniority for the shell model with realistic interactions , 2012, 1203.4856.

[7]  M. Caprio,et al.  Recursive calculation of matrix elements for the generalized seniority shell model , 2011, 1102.1479.

[8]  A. Arima,et al.  Emergence of generalized seniority in low-lying states with random interactions , 2011 .

[9]  A. Arima,et al.  Validity of pair truncations with effective interaction in Ca isotopes , 2010 .

[10]  J. Barea,et al.  Neutrinoless double- β decay in the microscopic interacting boson model , 2009 .

[11]  K. D. Sviratcheva,et al.  Underlying Symmetries of Realistic Interactions and the Nuclear Many-body Problem , 2006, nucl-th/0703075.

[12]  B. A. Brown,et al.  New effective interaction for pf-shell nuclei and its implications for the stability of the N = Z = 28 closed core , 2004, nucl-th/0402079.

[13]  P. Isacker,et al.  Odd-mass nickel isotopes in a generalized-seniority approach , 2002 .

[14]  I. Talmi.  Generalized seniority states with definite isospin , 2001 .

[15]  Jin-quan Chen.  Nucleon-pair shell model: Formalism and special cases , 1997 .

[16]  M. Hjorth-Jensen,et al.  Generalized seniority scheme in light Sn isotopes , 1996, nucl-th/9612052.

[17]  T. Otsuka.  Microscopic calculation of IBM in the Te-Ba region , 1993 .

[18]  B. A. Brown,et al.  New effective interactions for the 0f1p shell , 1991 .

[19]  A. Faessler,et al.  Microscopic IBA calculations of (e, e') M1 form factors☆ , 1990 .

[20]  X. Ji,et al.  Double beta decay in the generalized-seniority scheme , 1989 .

[21]  Y. K. Gambhir,et al.  The broken pair model for nuclei and its recent applications , 1988 .

[22]  Navrátil,et al.  Interacting boson-fermion model analysis of beta decay in A=195 and 197 nuclei. , 1988, Physical review. C, Nuclear physics.

[23]  I. Talmi,et al.  Shell-model foundations of the interacting boson model , 1987 .

[24]  A. Arima,et al.  The Interacting Boson Model: The interacting boson model-2 , 1987 .

[25]  A. Frank,et al.  Microscopic study of configuration mixing in the interacting boson model , 1986 .

[26]  G. T. Velde,et al.  Spectroscopy of even Sn nuclei and generalized-seniority breaking , 1985 .

[27]  S. Pittel,et al.  The structure of the S and D pairs of the interacting Boson Model from the Hartree-Fock-Bogolyubov approximation , 1983 .

[28]  O. Scholten,et al.  THE N = 82 ISOTONES IN THE GENERALIZED SENIORITY SCHEME , 1983 .

[29]  A. Vitturi,et al.  Microscopic structure of monopole and quadrupole bosons , 1983 .

[30]  I. Talmi.  Shell model foundations of the interacting boson model , 1983 .

[31]  S. Pittel,et al.  The microscopic Interacting Boson Model for nondegenerate orbits , 1982 .

[32]  A. Frank,et al.  Commutator algebra for the microscopic interacting boson model with nondegenerate orbits , 1982 .

[33]  T. Otsuka,et al.  Nuclear Shell Model and Interacting Bosons , 1978 .

[34]  I. Talmi,et al.  Shell model Hamiltonians with generalized seniority eigenstates , 1972 .

[35]  I. Talmi.  Generalized seniority and structure of semi-magic nuclei , 1971 .

[36]  Y. K. Gambhir,et al.  Number-conserving shell-model calculations for nickel and tin isotopes , 1971 .

[37]  Y. K. Gambhir,et al.  Number-conserving approximation to the shell model , 1969 .