Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: OPE of the pseudoscalar gluonium correlator in massless QCD to
  three-loop order   In this paper analytical results are presented for higher order corrections
to coefficient functions of the operator product expansion (OPE) for the
correlator of two pseudoscalar gluonium operators \tilde{O}_1=G^{\mu
\nu}\tilde{G}_{\mu \nu}. The Wilson coefficient in front of the scalar gluon
condensate operator O_1=-1/4 G^{\mu \nu}G_{\mu \nu} is given at three-loop
accuracy. The leading coefficient C_0 in front of the unity operator O_0=1 has
been calculated up to three-loop order some time ago but has been checked
independently in this work. It is interesting to see that the coefficient C_1
in the pseudoscalar case is finite, whereas contact terms appear in C_0 in this
case and in both coefficients C_0 and C_1 in the cases of the scalar gluonium
correlator and the energy momentum tensor correlator. For the corresponding
Renormalization Group invariant Wilson coefficients which are also constructed
the results are partially extended to four-loop accuracy. All results are given
in the MSbar-scheme at zero temperature.

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The categories of this paper are: stat
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: solv-int