Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Model space truncation in shell-model fits   We carry out an interacting shell-model study of binding energies and spectra
in the $sd$-shell nuclei to examine the effect of truncation of the shell-model
spaces. Starting with a Hamiltonian defined in a larger space and truncating to
the $sd$ shell, the binding energies are strongly affected by the truncation,
but the effect on the excitation energies is an order of magnitude smaller. We
then refit the matrix elements of the two-particle interaction to compensate
for the space truncation, and find that it is easy to capture 90% of the
binding energy shifts by refitting a few parameters. With the full parameter
space of the two-particle Hamiltonian, we find that both the binding energies
and the excitation energy can be fitted with remaining residual error about 5%
of the average error from the truncation. Numerically, the rms initial error
associated with our Hamiltonian is 3.4 MeV and the remaining residual error is
0.16 MeV. This is comparable to the empirical error found in $sd$-shell
interacting shell model fits to experimental data\cite{br06}.

16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
17
The categories of this paper are: q-fin
7
The categories of this paper are: hep-th
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph