Intruder bands and configuration mixing in the lead isotopes

Abstract

A three-configuration mixing calculation is performed in the context of the interacting boson model with the aim to describe recently observed collective bands built on low-lying $0^{+}$ states in neutron-deficient lead isotopes. The configurations that are included correspond to the regular, spherical states as well as two-particle two-hole and four-particle four-hole excitations across the Z=82 shell gap.

Comments: 20 pages, 4 figures, accepted by PRC, reference added for section 1 in this revised version