Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Neutron beta-decay and the quark-mixing CKM-matrix   Neutrons study a number of hot topics from the field of particle physics and
cosmology: Recent measurements of various mixed
American-British-French-German-Hungarian-Japan-Russian groups of researchers
determine the strength of the weak interaction of the neutron, which gives us
unique information on quark-mixing and the question of unitarity. Much to our
surprise, with neutron-decay we find a deviation Delta = 0.0083(28) from the
unitarity condition, an effect that cannot be explained by the current Standard
Model of particle physics.

21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
2
The categories of this paper are: math
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph