Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: X rays test the Pauli exclusion principle   Since the publication of the models describing a small violation of the Pauli
exclusion principle (PEP) there has been an explosion of word-wide interest in
PEP tests and related theories.
  PEP forbids an atom to have more than 2 electrons in the K-shell. If PEP is
slightly violated, a third electron can occasionally join in. This would result
in an anomalous X-ray emission. A high-sensitivity experiment places an upper
limit of the order of 10^{-26} on the PEP violating parameter.
  I will outline the main theoretical and experimental ideas in this new
exciting area.

1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
18
The categories of this paper are: econ
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an