Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dark photon limits: a handbook   The dark photon is a massive hypothetical particle that interacts with the
Standard Model by kinetically mixing with the visible photon. For small values
of the mixing parameter, dark photons can evade cosmological bounds to be a
viable dark matter candidate. Due to the similarities with the electromagnetic
signals generated by axions, several bounds on dark photon signals are simply
reinterpretations of historical bounds set by axion haloscopes. However, the
dark photon has a property that the axion does not: an intrinsic polarisation.
Due to the rotation of the Earth, accurately accounting for this polarisation
is nontrivial, highly experiment-dependent, and depends upon assumptions about
the dark photon's production mechanism. We show that if one does account for
the DP polarisation, and the rotation of the Earth, an experiment's discovery
reach can be enhanced by over an order of magnitude. We detail the strategies
that would need to be taken to properly optimise a dark photon search. These
include judiciously choosing the location and orientation of the experiment, as
well as strategically timing any repeated measurements. Experiments located at
$\pm$35$^\circ$ or $\pm$55$^\circ$ latitude, making three observations at
different times of the sidereal day, can achieve a sensitivity that is fully
optimised and insensitive to the dark photon's polarisation state, and hence
its production mechanism. We also point out that several well-known searches
for axions employ techniques for testing signals that preclude their ability to
set exclusion limits on dark photons, and hence should not be reinterpreted as
such.

12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
7
The categories of this paper are: hep-th
32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
31
The categories of this paper are: ao-sci
15
The categories of this paper are: nucl-ex
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga