Boson-fermion symmetries in the W-Pt region

Conference · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5901683

Warner, D D

The concept of symmetry in the Interacting Boson Model (IBM) description of even-even nuclei has proved to be one of the model's most important elements, because they provide benchmarks in the formulation of a unified description of a broad range of nuclei. The importance of the recently proposed symmetries in odd-even systems can thus be viewed in the same light, and their role in pointing to a simple prescription for the changing collective structure in odd A nuclei throughout a major shell is likely to prove even more essential, given the much greater complexity of the boson-fermion (IBFM) Hamiltonian. The group structure of a boson-fermion system is described by U/sup B/(6) x U/sup F/(m) where m specifies the number of states available to the odd fermion, and thus depends on the single particle space assumed. The ability to construct group chains corresponding to the symmetries SU(5), SU(3) or 0(6) depends on the value of m. Of the structures studied in detail to date, the case of m = 12 is the one with the broadest potential. The fermion is allowed to occupy orbits with j = 1/2, 3/2 and 5/2, so that the assumed single particle space corresponds to the negative parity states available to an odd neutron at the end of the N = 82-126 shell, namely, P/sub 1/2/, p/sub 3/2/ and f/sub 5/2/. The region of interest thus spans the W-Pt nuclei, and since one prerequisite for an odd-A symmetry is the existence of that same symmetry in the neighboring even-even core nucleus, the odd Pt nuclei around A = 196 offer the obvious testing ground for the 0(6) limit of U(6/12). The heavier even-even W nuclei, on the other hand, have the characteristics of an axial rotor, and hence the negative parity structure of the neighboring odd W isotopes offers the possibility to study the validity of the SU(3) limit. Given a definition and understanding of these two limits, the construction of a simple description of the transitional Os nuclei can be considered.

• Research Organization: Brookhaven National Lab., Upton, NY (USA)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5901683
• Report Number(s): BNL-36119; CONF-850159-2; ON: DE85009755
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BOSON-FERMION SYMMETRY
COLLECTIVE EXCITATIONS
DAYS LIVING RADIOISOTOPES
DYNAMICAL GROUPS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXCITATION
HEAVY NUCLEI
INTERACTING BOSON MODEL
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
LIE GROUPS
MATHEMATICAL MODELS
MINUTES LIVING RADIOISOTOPES
NILSSON-MOTTELSON MODEL
NUCLEAR MODELS
NUCLEI
O GROUPS
PLATINUM 195
PLATINUM ISOTOPES
RADIOISOTOPES
SHELL MODELS
STABLE ISOTOPES
SU GROUPS
SU-3 GROUPS
SYMMETRY
SYMMETRY GROUPS
TUNGSTEN 185
TUNGSTEN ISOTOPES