Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Systematic classification of two loop d = 4 Dirac neutrino mass models
  and the Diracness-dark matter stability connection   We provide a complete systematic classification of all two-loop realizations
of the dimension four operator for Dirac neutrino masses. Our classification is
multi-layered, starting first with a classification in terms of all possible
distinct two-loop topologies. Then we discuss the possible diagrams for each
topology. Model-diagrams originating from each diagram are then considered. The
criterion for genuineness is also defined and discussed at length. Finally, as
examples, we construct two explicit models which also serve to highlight the
intimate connection between the Dirac nature of neutrinos and dark matter
stability.

9
The categories of this paper are: nlin
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th