Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: OPE of the energy-momentum tensor correlator and the gluon condensate
  operator in massless QCD to three-loop order   The correlator of two gluonic operators plays an important role for example
in transport properties of a Quark Gluon Plasma (QGP) or in sum rules for
glueballs.
  In [1] an operator product expansion (OPE) at zero temperature was performed
for the correlators of two scalar operators $O_1=-\frac{1}{4} G^{\mu \nu}G_{\mu
\nu}$ and two QCD energy-momentum tensors $T^{\mu\nu}$. There we presented
analytical two-loop results for the Wilson coefficient $C_1$ in front of the
gluon condensate operator $O_1$. In this paper these results are extended to
three-loop order.
  The three-loop Wilson coefficient $C_0$ in front of the unity operator
$O_0=1$ was already presented in [1] for the $T^{\mu\nu}$-correlator. For the
$O_1$-correlator the coefficient $C_0$ is known to four loop order from [2].
For the correlator of two pseudoscalar operators
$\tilde{O}_1=\varepsilon_{\mu\nu\rho\sigma} G^{\mu \nu} G^{\rho \sigma}$ both
coefficients $C_0$ and $C_1$ were computed in [3] to three-loop order. At zero
temperature $C_0$ and $C_1$ are the leading Wilson coefficients in massless
QCD.

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The categories of this paper are: acc-phys
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The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
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The categories of this paper are: q-bio
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The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: stat