Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Identification of new isomers in $^{228}$Ac : Impact on dark matter
  searches   We report the identification of metastable isomeric states of $^{228}$Ac at
6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These
states are produced by the $\beta$-decay of $^{228}$Ra, a component of the
$^{232}$Th decay chain, with $\beta$ Q-values of 39.52 keV, 39.13 keV and 25.61
keV, respectively. Due to its low Q-value as well as the relative abundance of
$^{232}$Th and their progeny in low background experiments, these observations
potentially impact the low-energy background modeling of dark matter search
experiments.

6
The categories of this paper are: astro-ph
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin