Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Explaining the SM flavor structure with grand unified theories   We do not know why there are three fermion families in the Standard Model
(SM), nor can we explain the observed pattern of fermion masses and mixing
angles. Standard grand unified theories based on the SU(5) and SO(10) groups
fail to shed light on this issue, since they also contain three copies of
fermion representations of an enlarged gauge group. However, it does not need
to be so: the Standard Model families might be distributed over distinct
representations of a grand unified model, in which case the gauge symmetry
itself might discriminate the various families and explain (at least partially)
the flavor puzzle. The most ambitious version of this idea consists on
embedding all SM fermions in a single irreducible representation of the gauge
group.

24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc