Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gluon Excitations and Quark Chiral Symmetry in the Meson Spectrum: an
  Einbein Solution to the Large Degeneracy Problem of Light Mesons   A large approximate degeneracy of the excited hadron spectra, appears in the
light meson spectra measured at LEAR, suggesting a novel principal quantum
number n+j in QCD spectra. We recently showed that the large degeneracy could
not be understood with state of the art confining and chiral invariant quark
models, derived in a truncated Coulomb gauge. To search for a solution to this
problem, here we add the gluon or string degrees of freedom. Although
independently the quarks or the gluons would lead to a 2 n +j or 2 n +l
spectrum, adding them may lead to the desired n+j pattern.

13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
10
The categories of this paper are: q-bio
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
26
The categories of this paper are: bayes-an
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
19
The categories of this paper are: eess
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat