activity
20242026
collaborators

7 papers

hep-th2026

The perturbative Ricci flow in gravity

Robert V. Harlander, Yannick Kluth, Jonas T. Kohnen +1

We develop a perturbative formulation of the Ricci flow in gravity. Following steps analogous to the gradient flow in QCD, we supplement the usual Feynman rules for perturbative gr…

hep-lat2026

Heavy-Meson Bag Parameters using Gradient Flow

Matthew Black, Robert V. Harlander, Jonas T. Kohnen +4

We demonstrate the use of the gradient flow combined with the short flow-time expansion (GF+SFTX) as a renormalization procedure for four-quark operator matrix elements and associa…

hep-ph2026

Bag Parameters for Heavy Meson Lifetimes

Matthew Black, Robert V. Harlander, Jonas T. Kohnen +4

We calculate the dimension-six four-quark matrix elements describing heavy-meson lifetime ratios using the gradient flow with its short flow-time expansion as a renormaliza…

hep-ph2025

Short-flow-time expansion of non-singlet twist-two operators at next-to-next-to-leading order QCD

Robert V. Harlander, Jonas T. Kohnen, Andrea Shindler

The gradient-flow formalism provides a framework for the direct determination of moments of parton distribution functions (PDFs) from lattice QCD calculations. Their conversion fro…

hep-lat2025

Gradient flow for parton distribution functions: first application to the pion

Anthony Francis, Patrick Fritzsch, Robert V. Harlander +9

Parton distribution functions (PDFs) are central to precision QCD phenomenology. Their Mellin moments can be computed on the lattice, but direct determinations using local operator…

hep-ph2025

Two-loop gradient-flow renormalization of scalar QCD

J. Borgulat, N. Felten, R. V. Harlander +1

The gradient-flow formalism is applied to a non-Abelian gauge theory with scalar and fermionic particles, dubbed "scalar QCD". It is shown that the flowed scalar quark requires a f…