Stout smearing and Wilson flow in lattice perturbation theory

We present the expansion of stout smearing and the Wilson flow in lattice perturbation theory to order <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msubsup><a:mrow><a:mi>g</a:mi></a:mrow><a:mrow><a:mn>0</a:mn></a:mrow><a:mrow><a:mn>3</a:mn></a:mrow></a:msubsup></a:mrow></a:math>, which is suitable for one-loop calculations. As the Wilson flow is generated by infinitesimal stout smearing steps, the results are related to each other by taking the appropriate limits. We show how to apply perturbative stout smearing or Wilson flow to the Feynman rules of any lattice fermion action and illustrate them by calculating the self-energy of the clover-improved Wilson fermion. Published by the American Physical Society 2024