Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Towards a Next-to-Next-to-Leading Order analysis of matching in
  $B^0$-$\bar{B}^0$ mixing   We compute perturbative corrections to matching coefficients of QCD to HQET
for the matrix element of the $\Delta B=2$ operator that determines the mass
difference in $B^0-\bar{B}^0$ system of states. This involves the technical
point of choosing the operator basis in HQET, separating physical operators
from evanescent ones. We obtain an analytical result for some of the two-loop
corrections at order $\alpha_s^2$.

29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
1
The categories of this paper are: cs
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
35
The categories of this paper are: mtrl-th
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin