Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The $\Delta I = 1/2 $ Rule in the Light of Two-Dimensional QCD   We calculate in QCD$_2$ the ratios of baryonic matrix elements of $\Delta I =
2$ and $\Delta I = 0$ four-fermion operators, with a view to understanding
better the mechanism of $\Delta I = 1/2$ enhancement in QCD$_4$. We find
relatively small suppressions of both the scalar-scalar and vector-vector
$\Delta I = 2$ four-fermion operators. We discuss the possible implications of
these results, in view of a suggestion that gluon condensation may be an
important contributing factor in the $\Delta I = 1/2$ enhancement seen in
QCD$_4$. At the technical level, our calculation of the vector-vector operator
matrix element requires a treatment of the time dependence of the QCD$_2$
soliton which had not been developed in previous phenomenological calculations
within this model.

26
The categories of this paper are: bayes-an
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
12
The categories of this paper are: nucl-th