On improvement of the axial-vector current with stabilised Wilson fermions

TL;DR

This paper determines the improvement coefficient for the axial-vector current in lattice QCD with stabilised Wilson fermions, using Schrödinger functional techniques and exploring wavefunction variations.

Contribution

It introduces a method to accurately compute the improvement coefficient $c_A$ in three-flavor lattice QCD with stabilised Wilson-Clover fermions, enhancing precision in current improvement.

Findings

Determined $c_A$ for various gauge couplings.

Explored wavefunction variations for state generation.

Presented preliminary renormalisation constants $Z_V$ and $Z_A$.

Abstract

We report on the determination of the improvement coefficient $c_{\rm A}$ for the non-singlet axial-vector current $A^{a}_{\mu}(x)$ in the framework of stabilised Wilson-Clover fermions within three flavour lattice QCD. This is done by requiring the PCAC relation to hold for two different pseudo-scalar states. To generate these states, wavefunctions altering spatial structures on the boundaries of a Schr\"odinger functional lattice are employed and some variations of the (previously applied) wavefunction method are explored. The improvement coefficient is determined on a few ensembles for a range of gauge couplings that is potentially useful for future applications. Preliminary results on the renormalisation constants $Z_{\rm V}$ for the vector current and $Z_{\rm A}$ for the axial-vector current are also presented.