**Non-perturbative determination of improvement coefficients using coordinate space correlators in Nf=2+1 lattice QCD**

*P. Korcyl, G. Bali*

in 34th annual International Symposium on Lattice Field Theory

Contribution: pdf

**Abstract**

We determine quark mass dependent order $a$ improvement terms of the form $b_J am$ for non-singlet scalar,

pseudoscalar, vector and axialvector currents, using correlators in coordinate space. We use a set of CLS ensembles

comprising non-perturbatively improved Wilson Fermions and the tree-level Luescher-Weisz gauge action

at $\beta=3.4,3.46,3.55$ and $\beta=3.7$, corresponding to lattice spacings $a$ ranging from $0.05$ fm to $0.09$ fm.

We report the values of the $b_J$ improvement coefficients which are proportional to non-singlet quark

mass combinations and also discuss the possibility of determining the $\bar{b}_J$ coefficients which are proportional

to the trace of the quark mass matrix.