Non-perturbative renormalization of the axial current in Nf=3 lattice QCD with Wilson fermions and tree-level improved gauge action

Preprint number: CP3-Origins-2016-15 DNRF90 and DIAS-2016-15
Authors: John Bulava (Trinity College), Michele Della Morte (CP3-Origins), Jochen Heitger (Muenster University), and Christian Wittemeier (Muenster University)
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We non-perturbatively determine the renormalization factor of the axial vector current in lattice QCD with \(N_f=3\) flavors of Wilson-clover fermions and the tree-level Symanzik-improved gauge action. The (by now standard) renormalization condition is derived from the massive axial Ward identity and it is imposed among Schrödinger functional states with large overlap on the lowest lying hadronic state in the pseudoscalar channel, in order to reduce kinematically enhanced cutoff effects. We explore a range of couplings relevant for simulations at lattice spacings of \(\approx 0.09\) fm and below. An interpolation formula for \(Z_A(g_0^2)\), smoothly connecting the non-perturbative values to the 1-loop expression, is provided together with our final results.