Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Background field approach to electromagnetic properties of baryons   We investigate the self-energies of particles in an external magnetic field
$B$. The dependence is generally of the type $\sqrt{P(B)}$ with $P$ a
polynomial in $B$ and the participating masses. The non-analytic point depends
on the mass and charge constellations, is unproblematic for stable particles
but constrains the linear energy shift approximation for resonances. We
calculate the $B$ dependent self-energies of the nucleon and
$\Delta(1232)$-isobar in the SU(2) covariant chiral perturbation theory and
outline a way to obtain finite volume corrections to the nucleon anomalous
magnetic moment without using the three point function method. We show that
finite volume corrections might explain present discrepancies of lattice QCD
and chiral perturbation theory results in the small pion mass region.

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The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin