Systematic study of subbarrier fusion in rare-earth nuclei

Abstract

The recent accurate measurements of fusion cross sections at subbarrier energies have enabled extraction of barrier distributions which could provide a novel test for collective models. %e carry out a systematic study of subbarrier fusion in rare-earth nuclei using a scheme which incorporates the interacting boson model for nuclear structure effects. The existing data on vibrational and rotational nuclei are Gtted with a consistent set of parameters which are then used to predict the fusion cross sections and distribution of barriers in transitional nuclei. Contrary to vibrational and rotational nuclei where the cross sections increase smoothly with increasing deformation or mass number, transitional nuclei exhibit sharp changes in the barrier distribution due to shape-phase transitions.An accurate measurement of fusion cross sections for Pt and Os nuclei could thus provide a sensitive test for competing models in this region.

Signatures of multiphonon and neutron transfer couplings in the fusion ofS36,32+Stefanini1, Ackermann2, Corradi3 et al. 1995Phys. Rev. C

“…, by Coulomb excitation. Such data were also successfully analyzed in terms of CC calculations employing the interacting boson model to describe the structure of the colliding nuclei [10].Characteristic distributions are also predicted [11] for coupling to nucleon transfer channels with positive and negative Q values. More recently, nuclei without stable ground-state deformations were considered and our group performed a high-On leave from Shanghai Institute of Nuclear Research, Shanghai 201800, China. precision study of Ni+ Ni [12]; in this case, a barrier distribution with three clear peaks was observed, which could be explained by double-phonon couplings in both nuclei.…”

Description of nuclear structure effects in sub-barrier fusion by the interacting boson model

“…In this respect, the transitional Os-Pt region is of particular interest. One expects that barrier distributions for transitional nuclei exhibit sharp changes due to shape-phase transitions, contrary to vibrational and rotational nuclei where the cross sections increase smoothly with increasing deformation or mass number [13]. An accurate measurement of subbarrier fusion cross sections for transitional nuclei such as Pt and Os provides a sensitive test for competing models in this region and possibly point to new directions in research.…”

“…We carried out a systematic study of subbarrier fusion data, accumulated over the last few years, for rare-earth nuclei [13]. To illustrate the quality of this global fit, in Fig.…”

“…IBM based analysis of fusion cross sections describes the ANU data well [11,12,13,14], especially when the higher order coupling effects are included.…”

Symmetries, Supersymmetries, and Pairing in Nuclei

“…This is why the path integral method is very convenient when the internal structure is represented by an algebraic model such as the Interacting Boson Model. Using this approach it is possible to do systematic studies of subbarrier fusion cross sections [34] as well as other observables [35] not only for nuclei that are described by the dynamical symmetry limits, but also for transitional nuclei.…”