Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Redefining the Axion Window   A major goal of axion searches is to reach inside the parameter space region
of realistic axion models. Currently, the boundaries of this region depend on
somewhat arbitrary criteria, and it would be desirable to specify them in terms
of precise phenomenological requirements. We consider hadronic axion models and
classify the representations $R_Q$ of the new heavy quarks $Q$. By requiring
that $i)$ the $Q$ are sufficiently short lived to avoid issues with long lived
strongly interacting relics, $ii)$ no Landau poles are induced below the Planck
scale, fifteen cases are selected, which define a phenomenologically preferred
axion window bounded by a maximum (minimum) value of the axion-photon coupling
about twice (four times) larger than commonly assumed. Allowing for more than
one $R_Q$, larger couplings, as well as complete axion-photon decoupling,
become possible.

28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
15
The categories of this paper are: nucl-ex