Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Sufficiently Small $\bar{\theta}$ in $SU(3)^3 \times S_3$ Unification
  Model   Since CP violation in weak decays is successfully described by the KM
mechanism, the strong CP problem cannot easily be accommodated. This leads us
to reconsider the issue. If the axion and massless up quark are abandoned, we
must extend the standard model. Extension to $SU(3)^3 \times S_3$ unification
leads to the following situation: {\it if} CP is a high-energy symmetry and the
appropriate symmetry-breaking hierarchy of scales is in place, then the
$\bar{\theta}$ parameter of the QCD sub-theory is guaranteed to be sufficiently
small. We find $\bar{\theta} < 10^{-11}$ while the empirical limit from the
neutron electric dipole moment requires only that $\bar{\theta} < 1.3 \times
10^{-10}$.

9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg