Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Interplay between $SU(N_f)$ chiral symmetry, $U(1)_A$ axial anomaly and
  massless bosons   The standard wisdom on the origin of massless bosons in the spectrum of a
Quantum Field Theory $(QFT)$ describing the interaction of gauge fields coupled
to matter fields is based on two well known features: gauge symmetry, and
spontaneous symmetry breaking of continuous global symmetries. However we will
show in this article how the topological properties, that originate the
$U(1)_A$ axial anomaly in a $QFT$ which describes the interaction of fermion
matter fields and gauge bosons, are the basis of an alternative mechanism to
generate massless bosons in the chiral limit, if the non-abelian $SU(N_f)_A$
chiral symmetry is fulfilled in the vacuum. We will also test our predictions
with the results of a well known two-dimensional model, the two-flavour
Schwinger model, which was analyzed by Coleman long ago, and will give a
reliable answer to some of the questions he asked himself on the spectrum of
the model in the strong-coupling (chiral) limit. We will also analyze what are
the expectations for the $U(N)$ gauge-fermion model in two dimensions, and will
discuss on the impact of our results in the chirally symmetric high temperature
phase of $QCD$, which was present in the early universe, and is expected to be
created in heavy-ion collision experiments.

5
The categories of this paper are: gr-qc
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
18
The categories of this paper are: econ
2
The categories of this paper are: math
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga