Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On dipenguin contribution to D^0 - \bar D^0 mixing   We study the impact of the four-quark dipenguin operator to the D^0 - \bar
D^0 mixing. It is shown to contribute to the short distance piece at the same
order of magnitude as the box diagram.

21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
32
The categories of this paper are: atom-ph
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
9
The categories of this paper are: nlin