Gradient Flow Renormalisation for Meson Mixing and Lifetimes

arXiv (Cornell University)

Abstract

Fermionic gradient flow in combination with the short-flow-time expansion provides a computational method where the renormalisation of hadronic matrix elements on the lattice can be simplified to address e.g. the issue that operators with different mass dimension can mix. We demonstrate our gradient flow renormalisation procedure by determining matrix elements of four-quark operators describing neutral meson mixing or meson lifetimes. While meson mixing calculations are well-established on the lattice and serve to validate our procedure, a lattice calculation of matrix elements for heavy meson lifetimes is still outstanding. Preliminary results for mesons formed of a charm and strange quark are presented.

Authors 5

1. Robert V. Harlander Aachen Institute for Theoretical Particle Physics and Cosmology

   RWTH Aachen University

   Affiliation as printed

   Institute for Theoretical Particle Physics and Cosmology , RWTH Aachen University , 52056 Aachen , Germany

2. Fabian Lange

   Paul Scherrer Institute

   Affiliation as printed

   PSI Center for Neutron and Muon Sciences , 5232 Villigen PSI , Switzerland

3. Antonio Rago

   University of Southern Denmark

   Affiliation as printed

   IMADA and Quantum Theory Center , University of Southern Denmark , Odense , Denmark

4. Andrea Shindler
5. Oliver Witzel