Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Chiral perturbation theory and nucleon-pion-state contaminations in
  lattice QCD   Multi-particle states with additional pions are expected to be a
non-negligible source of excited-state contamination in lattice simulations at
the physical point. It is shown that baryon chiral perturbation theory can be
employed to calculate the contamination due to two-particle nucleon-pion states
in various nucleon observables. Leading order results are presented for the
nucleon axial, tensor and scalar charge and three Mellin moments of parton
distribution functions (quark momentum fraction, helicity and transversity
moment). Taking into account phenomenological results for the charges and
moments the impact of the nucleon-pion-states on lattice estimates for these
observables can be estimated. The nucleon-pion-state contribution results in an
overestimation of all charges and moments obtained with the plateau method. The
overestimation is at the 5-10% level for source-sink separations of about 2 fm.
The source-sink separations accessible in contemporary lattice simulations are
found to be too small for chiral perturbation theory to be directly applicable.

6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
18
The categories of this paper are: econ
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
4
The categories of this paper are: cond-mat