Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instantaneous Bethe-Salpeter Kernel for the Lightest Pseudoscalar Mesons   Starting from a phenomenologically successful, numerical solution of the
Dyson-Schwinger equation that governs the quark propagator, we reconstruct in
detail the interaction kernel that has to enter the instantaneous approximation
to the Bethe-Salpeter equation to allow us to describe the lightest
pseudoscalar mesons as quark-antiquark bound states exhibiting the (almost)
masslessness necessary for them to be interpretable as the (pseudo) Goldstone
bosons related to the spontaneous chiral symmetry breaking of quantum
chromodynamics.

9
The categories of this paper are: nlin
18
The categories of this paper are: econ
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
20
The categories of this paper are: acc-phys
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
11
The categories of this paper are: hep-lat