Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Effects of dark atom excitations   New stable quarks and charged leptons may exist and be hidden from detection,
as they are bound by Coulomb interaction in neutral dark atoms of composite
dark matter. This possibility leads to fundamentally new types of indirect
effects related to the excitation of such dark atoms followed by their
electromagnetic de-excitation. Stable -2 charged particles, bound to primordial
helium in O-helium (OHe) atoms, represent the simplest model of dark atoms.
Here we consider the structure of OHe atomic levels which is a necessary input
for the indirect tests of such composite dark matter scenarios, and we give the
spectrum of electromagnetic transitions from the levels excited in OHe
collisions.

32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph