Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The electromagnetic effects in $K_{e4}$ decay   The final state interaction of pions in $K_{e4}$ decay allows one to obtain
the value of the isospin and angular momentum zero $\pi\pi$ scattering length
$a_0^0$.We take into account the electromagnetic interaction of pions and
isospin symmetry breaking effects caused by different masses of neutral and
charged pions and estimate the impact of these effects on the procedure of
scattering length extraction from $K_{e4}$ decay.

17
The categories of this paper are: q-fin
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ