arXiv subjects

Robert H. Mason

Publications and source records attributed to Robert H. Mason.

2 recordsLinked to original sources

arXiv2026

The gradient-flow coupling of three-and four-dimensional QED

We evaluate the QED coupling in the gradient-flow scheme in three and four space-time dimensions. Our general result applies to any theory with a U(1) gauge field coupled to arbitary other fields via arbitrary interactions. As an example, we consider QED with $n_\text{f}$ flavors in three and four space-time dimensions and evaluate the corresponding $β$ functions. In four dimensions, we find that the perturbative expansion of the $β$ function behaves much better than the corresponding expression in QCD. In three dimensions, we recover both the ultraviolet as well as the infrared fixed points of the QED coupling in the large-$n_\text{f}$ limit.

hep-ph↗

arXiv2025

Quark-mass effects in gradient-flow observables through next-to-next-to-leading order in QCD

We provide results for the vacuum expectation values of the flowed action density, the quark condensate, and the quark kinetic operator in the gradient-flow formalism. We work in $N_\text{F}$-flavor QCD, keeping the heaviest quark massive and all others massless. The vacuum expectation values of these operators are calculated numerically through next-to-next-to-leading order QCD, providing important input for the extraction of fundamental QCD parameters from lattice calculations. While the focus is on charm- and bottom-quark mass effects, we provide the results in a form that is independent of the specific quark mass.

hep-lat↗