Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An experiment for the measurement of the bound-beta decay of the free
  neutron   The hyperfine-state population of hydrogen after the bound-beta decay of the
neutron directly yields the neutrino left-handedness or a possible right-handed
admixture and possible small scalar and tensor contributions to the weak force.
Using the through-going beam tube of a high-flux reactor, a background free
hydrogen rate of ca. 3 s$^{-1}$ can be obtained. The detection of the neutral
hydrogen atoms and the analysis of the hyperfine states is accomplished by Lamb
shift source type quenching and subsequent ionization. The constraints on the
neutrino helicity and the scalar and tensor coupling constants of weak
interaction can be improved by a factor of ten.

19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an