Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding the $f_0(980)$ and $a_0(980)$ masses as well as their
  widths   The low and approximately equal masses of the scalar mesons $f_0(980)$ and
$a_0(980)$, as well as their relatively small decay widths, are impossible to
understand in terms of standard $P$-wave quark-antiquark states. Here, these
mesons are studied in a unitarised quark-meson model, together with the other
light isoscalar scalar $f_0(500)$, as members of a complete scalar nonet below
about 1 GeV. They are shown to be dynamical states generated by a combination
of quark-confinement and strong-decay interactions, resulting in a large
breaking of $SU(3)_{\rm flavour}$ symmetry. This is illustrated with several
pole trajectories in the complex-energy plane as a function of the model's
decay coupling constant. Also, experimental evidence is presented of a still
much lighter scalar boson called $E(38)$, which may correspond to a novel kind
of mesons predicted by V. N. Gribov, as an observable manifestation of a
condensate of light quarks.

20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg