Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase space factors for $\beta^+\beta^+$ decay and competing modes of
  double-$\beta$ decay   A complete and improved calculation of phase space factors (PSF) for
$2\nu\beta^+\beta^+$ and $0\nu\beta^+\beta^+$ decay, as well as for the
competing modes $2\nu EC\beta^+$, $0\nu EC\beta^+$, and $2\nu ECEC$, is
presented. The calculation makes use of exact Dirac wave functions with finite
nuclear size and electron screening and includes life-times, single and summed
positron spectra, and angular positron correlations.

32
The categories of this paper are: atom-ph
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
5
The categories of this paper are: gr-qc
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
1
The categories of this paper are: cs
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
0
The categories of this paper are: hep-ph
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org