Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dark Matter searches through cross-correlations of gamma rays with
  neutral-hydrogen intensity mapping   In this work we derive the first theoretical prediction of the
cross-correlation signal between the unresolved gamma-ray background and the
21-cm line originated by the spin-flip transition of neutral hydrogen atoms, by
taking as benchmark experiment the space telescope {\it Fermi}-LAT for gamma
rays and the next-generation radio telescope Square Kilometer Array (SKA) as
well as its precursor MeerKAT for the 21-cm emission. The attainable bounds in
the dark matter (DM) parameter space are envisioned to be competitive already
with the combination {\it Fermi}-LAT $\times$ MeerKAT, but SKA will allow to go
deeper and probe a thermal DM particle up to masses of 130 GeV. A future
gamma-ray detector with better angular resolution and larger exposure together
with an ungraded radio telescope will have the potentiality to probe a DM
candidate with thermal annihilation cross-section and masses up to the TeV
scale.

5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con