Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: $N\pi$-states and the projection method for the nucleon axial and
  pseudoscalar form factors   The RQCD collaboration proposed a projection method to remove the excited
state contamination in lattice OCD calculations of nuclear form factors. The
effectiveness of this method in removing the two-particle nucleon-pion-state
contamination is examined using chiral perturbation theory. It is shown that
the projection method has practically no impact in the calculation of the axial
and induced pseudoscalar form factors. In the pseudoscalar form factor the
projection method strongly enhances the nucleon-pion-state contamination. The
generalized Goldberger-Treiman relation is satisfied even though large
nucleon-pion-state contaminations are present in individual form factors.
Therefore, the projection method is not a solution to the excited state problem
in nucleon form factor calculations.

31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
20
The categories of this paper are: acc-phys
2
The categories of this paper are: math
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
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
1
The categories of this paper are: cs
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The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ