Gauge field smearing and controlled continuum extrapolations

by Andreas Risch

Tuesday 6 May 2025, 16:00 → 18:00 Europe/Zurich

4/2-037 - TH meeting room (CERN)

Two popular methods to reduce discretisation effects are Symanzik improvement and gauge field smearing in the Dirac operator. Tree-level $O(a^2)$-improved Wilson fermions can be obtained from $O(a)$-improved Wilson fermions by adding one dimension-6 operator to the action. For gauge field smearing one wants to avoid the situation when too much smearing leads to uncontrolled continuum extrapolations as the short distance behaviour of the theory is mutilated. As a smearing prescription we focus on the gradient flow formalism as it allows to study both smearing and physical flow simultaneously. We investigate the effect of smearing and physical flow on the scaling towards the continuum limit in pure gauge theory. We focus on the example of Creutz ratios, which provide a measure of the physical forces felt by the fermions. For suitable smearing strengths we further investigate the impact of replacing the Wilson gradient flow by stout smearing.