Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Level density and $\gamma$-ray strength in $^{27,28}$Si   A method to extract simultaneously level densities and $\gamma$-ray
transmission coefficients has for the first time been tested on light nuclei
utilizing the $^{28}$Si($^3$He,$\alpha\gamma)^{27}$Si and
$^{28}$Si($^3$He,$^3$He'$\gamma)^{28}$Si reactions. The extracted level
densities for $^{27}$Si and $^{28}$Si are consistent with the level densities
obtained by counting known levels in the respective nuclei. The extracted
$\gamma$-ray strength in $^{28}$Si agrees well with the known $\gamma$-decay
properties of this nucleus. Typical nuclear temperatures are found to be $T\sim
2.4$ MeV at around 7 MeV excitation energy. The entropy gap between nuclei with
mass number $A$ and $A\pm 1$ is measured to be $\delta S\sim 1.0 k_B$, which
indicates an energy spacing between single-particle orbitals comparable with
typical nuclear temperatures.

34
The categories of this paper are: chem-ph
19
The categories of this paper are: eess
20
The categories of this paper are: acc-phys
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
8
The categories of this paper are: hep-ex