Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-loop renormalization of the electric charge in the Standard Model   We discuss the renormalization of the electric charge at the two-loop level
in the Standard Model of the electroweak interactions. We explicitly calculate
the expression of the complete on-shell two-loop counterterm using the
Background Field Method and discuss the advantages of this computational
approach. We consider the related quantity $\hat e(\mu)$, defined in the $\ms$
renormalization scheme and present numerical results for different values of
the scale $\mu$. We find that the full 2-loop electroweak corrections
contribute more than 10 parts in units $10^{-5}$ to the $\Delta \hat\alpha
(\mz^2)$ parameter, obtaining $\hat\alpha^{-1}(\mz)= 128.12 \pm 0.05$ for
$\Delta\alpha_{had}(\mz^2) =0.027572 \pm 0.000359$.

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The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
22
The categories of this paper are: chao-dyn
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
13
The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys