Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radiative electron capture in the first forbidden unique decay of 81Kr   The photon spectrum accompanying the orbital K-electron capture in the first
forbidden unique decay of 81Kr was measured. The total radiation intensity for
the photon energies larger than 50 keV was found to be 1.47(6) x 10^{-4} per
K-capture. Both the shape of the spectrum and its intensity relative to the
ordinary, non-radiative capture rate, are compared to theoretical predictions.
The best agreement is found for the recently developed model which employs the
length gauge for the electromagnetic field.

37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
18
The categories of this paper are: econ
6
The categories of this paper are: astro-ph