Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Instanton Triggered Chiral Symmetry Breaking, the U(1) Problem and a
  Possible Solution to the Strong CP Problem   We argue that instantons play a crucial role in triggering the spontaneous
breaking of chiral symmetry in the physics of the three light quarks in quantum
chromodynamics. However, instantons may also play an essential role in our
understanding of the suppression of CP violation in the strong interactions. We
revive the possibility that the bare mass of the up quark is identically zero
and the apparent small up quark mass is generated by the effective quark
dynamics associated with instantons. In this case, the strong CP phase becomes
unobservable and there is no strong CP violation.

8
The categories of this paper are: hep-ex
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn