Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Extended analysis of the "penguin" part of $K\to\pi\pi$ amplitude   We make an attempt to clarify the role of the annihilation or "penguin" mode
in the description of the $K\rightarrow\pi\pi$ decay within the Standard Model.
The attention is concentrated on new operators in the effective $\Delta S=1$
Hamiltonian and the violation of factorization for mesonic matrix elements of
the local four-quark operators. We propose a regular method to evaluate the
mesonic matrix elements of $K\rightarrow\pi\pi$ transitions based on studying
three-point correlators via {\it QCD} sum rules using the chiral effective
theory as an underlying low-energy model for strong interaction. Matrix
elements of the {\it QCD} penguin operator are calculated within this approach.
The total "penguin" contribution is found to be relatively large that improves
the theoretical description of the $\Delta I=1/2$ rule in non-leptonic kaon
decays.

8
The categories of this paper are: hep-ex
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math