https://doi.org/10.1140/epjc/s10052-020-8266-2
Regular Article - Theoretical Physics
Ward identity determination of 
for 
lattice QCD in a Schrödinger functional setup
1
Institut für Theoretische Physik, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 9, 48149, Münster, Germany
2
“Rome Tor Vergata” Division, c/o Dipartimento di Fisica, INFN, Via della Ricerca Scientifica 1, 00133, Rome, Italy
* e-mail: fabian.joswig@wwu.de
Received:
12
May
2020
Accepted:
21
July
2020
Published online:
24
August
2020
We derive chiral Ward identities for lattice QCD with Wilson quarks and 
flavours, on small lattices with Schrödinger functional boundary conditions and vanishingly small quark masses. These identities relate the axial variation of the non-singlet pseudoscalar density to the scalar one, thus enabling the non-perturbative determination of the scale-independent ratio of the renormalisation parameters of these operators. We obtain results for 
QCD with tree-level Symanzik-improved gluons and Wilson-Clover quarks, for bare gauge couplings which cover the typical range of large-volume 
simulations with Wilson fermions at lattice spacings below 
fm. The precision of our results varies from 0.3 to 1%, except for the coarsest lattice, where it is 2%. We discuss how the ratio can be used in the non-perturbative calculations of 
improved renormalised quark masses.
© The Author(s), 2020
