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Large mass expansion in two-loop QCD corrections of para-charmonium decay

K. Hasegawa·Alexey Pak
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Abstract

We calculate the two-loop QCD corrections to paracharmonium decays $eta_{c} rightarrow gamma gamma$ and $eta_{c} rightarrow g g$ involving light-by-light scattering diagrams with light quark loops. Artificial large mass expansion and convergence improvement techniques are used to evaluate these corrections. The obtained corrections to the decays $eta_{c} rightarrow gamma gamma$ and $eta_{c} rightarrow g g$ account for $-1.25 %$ and $ -0.73 %$ of the leading order contribution, respectively.

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K. Hasegawa, Alexey Pak. 2008-01-16. Large mass expansion in two-loop QCD corrections of para-charmonium decay. https://doi.org/10.1103/physrevd.77.017503

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