Why the Fermion Dynamical Symmetry Model Fails to Predict Nuclear Masses:
a Comprehensive Assessment
Ragnar Bengtsson
Department of Mathematical Physics, Lund Institute of Technology,
P. O. Box 118, Sweden
and
Peter Möller
Theoretical Division, Los Alamos National Laboratory,
New Mexico 87545, USA
Abstract:
In the last several years new experimental data have become available
on alpha-decay chains starting in the predicted deformed superheavy
region near 272110. This has promoted new interest in
nuclear mass formulas and how well they
extrapolate to regions far beyond where experimental masses were
previously known. We here focus on two such mass models, namely the
fermion dynamical symmetry model and the finite-range droplet
model. We have chosen these models, since they both reproduce
previously known actinide masses with good accuracy, but rapidly
diverge from each other in the region of the recently observed new
elements. Furthermore, the two models have been the subject to
animated discussions concerning which one gives the most reliable
predictions of nuclear masses in the superheavy region and in the
terminating region of the r-process. The new data support the
predictions of the finite-range droplet model. We discuss the fermion
dynamical symmetry model and its application [1] to the
calculation of trans-Pb nuclear masses. As will be shown, the model
contains unphysical features and has many more free constants than
claimed. The values obtained for the constants and the model
agreement with data in the region of adjustment are therefore of no
particular significance and severe divergences occur for recently
discovered nuclei outside the region of adjustment.
The text and
figures are available
for download.
This manuscript has been assigned Los Alamos Preprint No LA-UR-00-0921
and appears in
Phys. Rev. C 64 (2001) 014308.
Peter Moller
Created: 2001 -->
Last modified: Tue Jul 2 2012