Isomers And E0 Transitions As A Probe Of Triple Shape Co-existence In 188Pb.

New structures above and below the two-particle isomeric states in [sup 188]Pb have been identified. Their properties are consistent with the presence of three minima in the nuclear potential well, associated with spherical, weakly oblate and substantial prolate deformations. The fragmented decay of the weakly populated K[sup π] = 8[sup -], 1 µs prolate isomer also provides a means of identifying non-yrast low-spin structures which are otherwise inaccessible. Through this mechanism, collective bands which can be associated with the excited 0[sup +] states have been identified and E0 transitions between them inferred. Analysis of the excitation energies, branching ratios and E2/E0 decay-width ratios through a band-mixing model provides a test of shape differences and the separability of the wave functions at low spin. [ABSTRACT FROM AUTHOR]