Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quark-antiquark Bethe-Salpeter formalism, spectrum and Regge
  Trajectories   Starting from a path integral representation of appropriate 4-point and
2-point gauge invariant Green functions and from the "Modified Area Law" model
for the evaluation of the Wilson loop, a q \bar q Bethe-Salpeter like equation
and a related Schwinger-Dyson equation can be obtained. From such equations an
effective relativistic Hamiltonian can be derived by standard methods and then
applied to the determination of the meson spectrum. The entire known
heavy-heavy and heavy-light spectra and the lowest light-light Regge
trajectories are rather well reproduced in terms of four parameters alone, the
light quark masses being fixed a priori on typical current values.

17
The categories of this paper are: q-fin
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
25
The categories of this paper are: patt-sol